05-05-2017, 06:53 PM
140 is an abundant number and a harmonic divisor number.[1] It is the sum of the squares of the first seven integers, which makes it a square pyramidal number, and in base 10 it is divisible by the sum of its digits, which makes it a Harshad number.
140 is an odious number because it has an odd number of ones in its binary number. The sum of Euler's totient function φ(x) over the first twenty-one integers is 140.
140 is a repdigit in bases 13, 19, 27, 34, 69, and 139.
140 is an odious number because it has an odd number of ones in its binary number. The sum of Euler's totient function φ(x) over the first twenty-one integers is 140.
140 is a repdigit in bases 13, 19, 27, 34, 69, and 139.