261583913 has 4 divisors (see below), whose sum is σ = 276971220. Its totient is φ = 246196608.

The previous prime is 261583873. The next prime is 261583919. The reversal of 261583913 is 319385162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 78712384 + 182871529 = 8872^2 + 13523^2 .

It is a cyclic number.

It is not a de Polignac number, because 261583913 - 2²⁰ = 260535337 is a prime.

It is a super-2 number, since 2×261583913² = 136852287080783138, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261583919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7693628 + ... + 7693661.

It is an arithmetic number, because the mean of its divisors is an integer number (69242805).

Almost surely, 2^261583913 is an apocalyptic number.

It is an amenable number.

261583913 is a deficient number, since it is larger than the sum of its proper divisors (15387307).

261583913 is a wasteful number, since it uses less digits than its factorization.

261583913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15387306.

The product of its digits is 38880, while the sum is 38.

The square root of 261583913 is about 16173.5559788193. Note that the first 3 decimals coincide. The cubic root of 261583913 is about 639.5438750317.

The spelling of 261583913 in words is "two hundred sixty-one million, five hundred eighty-three thousand, nine hundred thirteen".