155272571721 has 12 divisors (see below), whose sum is σ = 225444692148. Its totient is φ = 102978699264.

The previous prime is 155272571653. The next prime is 155272571731. The reversal of 155272571721 is 127175272551.

155272571721 is a `hidden beast` number, since 1 + 5 + 5 + 2 + 7 + 2 + 571 + 72 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 99404631225 + 55867940496 = 315285^2 + 236364^2 .

It is not a de Polignac number, because 155272571721 - 2³⁴ = 138092702537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (155272571731) 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, 44693880 + ... + 44697353.

It is an arithmetic number, because the mean of its divisors is an integer number (18787057679).

Almost surely, 2^155272571721 is an apocalyptic number.

It is an amenable number.

155272571721 is a deficient number, since it is larger than the sum of its proper divisors (70172120427).

155272571721 is a wasteful number, since it uses less digits than its factorization.

155272571721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89391432 (or 89391429 counting only the distinct ones).

The product of its digits is 343000, while the sum is 45.

The spelling of 155272571721 in words is "one hundred fifty-five billion, two hundred seventy-two million, five hundred seventy-one thousand, seven hundred twenty-one".