261608913 has 32 divisors (see below), whose sum is σ = 402960000. Its totient is φ = 167541696.

The previous prime is 261608911. The next prime is 261608917. The reversal of 261608913 is 319806162.

It is not a de Polignac number, because 261608913 - 2¹ = 261608911 is a prime.

It is a super-2 number, since 2×261608913² = 136878446722083138, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261608911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 178578 + ... + 180036.

It is an arithmetic number, because the mean of its divisors is an integer number (12592500).

Almost surely, 2^261608913 is an apocalyptic number.

It is an amenable number.

261608913 is a deficient number, since it is larger than the sum of its proper divisors (141351087).

261608913 is a wasteful number, since it uses less digits than its factorization.

261608913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1726 (or 1720 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 261608913 is about 16174.3288268787. The cubic root of 261608913 is about 639.5642484654.

The spelling of 261608913 in words is "two hundred sixty-one million, six hundred eight thousand, nine hundred thirteen".