155265021 has 6 divisors (see below), whose sum is σ = 224271710. Its totient is φ = 103510008.

The previous prime is 155264951. The next prime is 155265023. The reversal of 155265021 is 120562551.

155265021 is a `hidden beast` number, since 1 + 5 + 5 + 2 + 650 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 154032921 + 1232100 = 12411^2 + 1110^2 .

It is a de Polignac number, because none of the positive numbers 2^k-155265021 is a prime.

It is a super-2 number, since 2×155265021² = 48214453492260882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155265023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8625826 + ... + 8625843.

Almost surely, 2^155265021 is an apocalyptic number.

It is an amenable number.

155265021 is a deficient number, since it is larger than the sum of its proper divisors (69006689).

155265021 is a wasteful number, since it uses less digits than its factorization.

155265021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17251675 (or 17251672 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 155265021 is about 12460.5385517641. The cubic root of 155265021 is about 537.4745137366.

The spelling of 155265021 in words is "one hundred fifty-five million, two hundred sixty-five thousand, twenty-one".