261657072 has 30 divisors (see below), whose sum is σ = 732276792. Its totient is φ = 87218976.

The previous prime is 261657059. The next prime is 261657089. The reversal of 261657072 is 270756162.

261657072 is a `hidden beast` number, since 2 + 6 + 16 + 570 + 72 = 666.

261657072 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×261657072² = 136928846655226368, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 908388 + ... + 908675.

Almost surely, 2^261657072 is an apocalyptic number.

It is an amenable number.

261657072 is an abundant number, since it is smaller than the sum of its proper divisors (470619720).

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

261657072 is a wasteful number, since it uses less digits than its factorization.

261657072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817077 (or 1817068 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 261657072 is about 16175.8175063890. The cubic root of 261657072 is about 639.6034913751.

The spelling of 261657072 in words is "two hundred sixty-one million, six hundred fifty-seven thousand, seventy-two".