155975121 has 27 divisors (see below), whose sum is σ = 236827227. Its totient is φ = 98912880.

The previous prime is 155975101. The next prime is 155975159. The reversal of 155975121 is 121579551.

The square root of 155975121 is 12489.

It is a perfect power (a square), and thus also a powerful number.

155975121 is a `hidden beast` number, since 1 + 55 + 97 + 512 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1718721 + 154256400 = 1311^2 + 12420^2 .

It is a de Polignac number, because none of the positive numbers 2^k-155975121 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (155975101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 861651 + ... + 861831.

Almost surely, 2^155975121 is an apocalyptic number.

155975121 is the 12489-th square number.

155975121 is the 6245-th centered octagonal number.

It is an amenable number.

155975121 is a deficient number, since it is larger than the sum of its proper divisors (80852106).

155975121 is an equidigital number, since it uses as much as digits as its factorization.

155975121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414 (or 207 counting only the distinct ones).

The product of its digits is 15750, while the sum is 36.

The cubic root of 155975121 is about 538.2926423910.

Multiplying 155975121 by its sum of digits (36), we get a square (5615104356 = 74934²).

The spelling of 155975121 in words is "one hundred fifty-five million, nine hundred seventy-five thousand, one hundred twenty-one".