261636120 has 96 divisors (see below), whose sum is σ = 900357120. Its totient is φ = 65664000.

The previous prime is 261636091. The next prime is 261636181. The reversal of 261636120 is 21636162.

261636120 is a `hidden beast` number, since 2 + 6 + 1 + 636 + 1 + 20 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15256 + ... + 27495.

It is an arithmetic number, because the mean of its divisors is an integer number (9378720).

Almost surely, 2^261636120 is an apocalyptic number.

261636120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261636120 is an abundant number, since it is smaller than the sum of its proper divisors (638721000).

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

261636120 is a wasteful number, since it uses less digits than its factorization.

261636120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42785 (or 42778 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 261636120 is about 16175.1698600046. The cubic root of 261636120 is about 639.5864189910.

The spelling of 261636120 in words is "two hundred sixty-one million, six hundred thirty-six thousand, one hundred twenty".