155913921 has 12 divisors (see below), whose sum is σ = 226109520. Its totient is φ = 103527000.

The previous prime is 155913917. The next prime is 155913949. The reversal of 155913921 is 129319551.

155913921 is a `hidden beast` number, since 1 + 559 + 13 + 92 + 1 = 666.

It is not a de Polignac number, because 155913921 - 2² = 155913917 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (155913971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32251 + ... + 36768.

It is an arithmetic number, because the mean of its divisors is an integer number (18842460).

Almost surely, 2^155913921 is an apocalyptic number.

It is an amenable number.

155913921 is a deficient number, since it is larger than the sum of its proper divisors (70195599).

155913921 is a wasteful number, since it uses less digits than its factorization.

155913921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69276 (or 69273 counting only the distinct ones).

The product of its digits is 12150, while the sum is 36.

The square root of 155913921 is about 12486.5496034733. The cubic root of 155913921 is about 538.2222298382. Note that the first 5 decimals are identical.

The spelling of 155913921 in words is "one hundred fifty-five million, nine hundred thirteen thousand, nine hundred twenty-one".