261632556 has 18 divisors (see below), whose sum is σ = 661349052. Its totient is φ = 87210840.

The previous prime is 261632549. The next prime is 261632557. The reversal of 261632556 is 655236162.

It is a happy number.

261632556 is a `hidden beast` number, since 2 + 616 + 32 + 5 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-3 number, since 3×261632556³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 7267571 = 261632556 / (2 + 6 + 1 + 6 + 3 + 2 + 5 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 261632556.

It is not an unprimeable number, because it can be changed into a prime (261632557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3633750 + ... + 3633821.

It is an arithmetic number, because the mean of its divisors is an integer number (36741614).

Almost surely, 2^261632556 is an apocalyptic number.

It is an amenable number.

261632556 is an abundant number, since it is smaller than the sum of its proper divisors (399716496).

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

261632556 is a wasteful number, since it uses less digits than its factorization.

261632556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7267581 (or 7267576 counting only the distinct ones).

The product of its digits is 64800, while the sum is 36.

The square root of 261632556 is about 16175.0596907709. The cubic root of 261632556 is about 639.5835148350.

The spelling of 261632556 in words is "two hundred sixty-one million, six hundred thirty-two thousand, five hundred fifty-six".