261513504 has 72 divisors (see below), whose sum is σ = 849925440. Its totient is φ = 74717568.

The previous prime is 261513491. The next prime is 261513509. The reversal of 261513504 is 405315162.

261513504 is a `hidden beast` number, since 2 + 6 + 151 + 3 + 504 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is not an unprimeable number, because it can be changed into a prime (261513509) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62844 + ... + 66875.

It is an arithmetic number, because the mean of its divisors is an integer number (11804520).

Almost surely, 2^261513504 is an apocalyptic number.

261513504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

261513504 is an abundant number, since it is smaller than the sum of its proper divisors (588411936).

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

261513504 is a wasteful number, since it uses less digits than its factorization.

261513504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129742 (or 129731 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 261513504 is about 16171.3791619639. The cubic root of 261513504 is about 639.4864891309.

Adding to 261513504 its reverse (405315162), we get a palindrome (666828666).

The spelling of 261513504 in words is "two hundred sixty-one million, five hundred thirteen thousand, five hundred four".