156691980 has 72 divisors (see below), whose sum is σ = 490648704. Its totient is φ = 40435200.

The previous prime is 156691973. The next prime is 156691991. The reversal of 156691980 is 89196651.

156691980 is a `hidden beast` number, since 1 + 566 + 9 + 1 + 9 + 80 = 666.

156691980 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8461 + ... + 19620.

Almost surely, 2^156691980 is an apocalyptic number.

156691980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

156691980 is an abundant number, since it is smaller than the sum of its proper divisors (333956724).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

156691980 is a wasteful number, since it uses less digits than its factorization.

156691980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28127 (or 28122 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The square root of 156691980 is about 12517.6667154866. Note that the first 3 decimals coincide. The cubic root of 156691980 is about 539.1160435032.

The spelling of 156691980 in words is "one hundred fifty-six million, six hundred ninety-one thousand, nine hundred eighty".