261555536 has 30 divisors (see below), whose sum is σ = 557025546. Its totient is φ = 118888000.

The previous prime is 261555527. The next prime is 261555589. The reversal of 261555536 is 635555162.

It can be written as a sum of positive squares in only one way, i.e., 145347136 + 116208400 = 12056^2 + 10780^2 .

It is a super-2 number, since 2×261555536² = 136822596824494592, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261555536.

It is a congruent number.

It is an unprimeable number.

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, 65615 + ... + 69486.

Almost surely, 2^261555536 is an apocalyptic number.

It is an amenable number.

261555536 is an abundant number, since it is smaller than the sum of its proper divisors (295470010).

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

261555536 is a wasteful number, since it uses less digits than its factorization.

261555536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135131 (or 135114 counting only the distinct ones).

The product of its digits is 135000, while the sum is 38.

The square root of 261555536 is about 16172.6786896915. The cubic root of 261555536 is about 639.5207479815.

The spelling of 261555536 in words is "two hundred sixty-one million, five hundred fifty-five thousand, five hundred thirty-six".