261664156 has 24 divisors (see below), whose sum is σ = 497511504. Its totient is φ = 119696640.

The previous prime is 261664133. The next prime is 261664157. The reversal of 261664156 is 651466162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261664157) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16390 + ... + 28141.

It is an arithmetic number, because the mean of its divisors is an integer number (20729646).

Almost surely, 2^261664156 is an apocalyptic number.

261664156 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

261664156 is a deficient number, since it is larger than the sum of its proper divisors (235847348).

261664156 is a wasteful number, since it uses less digits than its factorization.

261664156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44661 (or 44659 counting only the distinct ones).

The product of its digits is 51840, while the sum is 37.

The square root of 261664156 is about 16176.0364737472. The cubic root of 261664156 is about 639.6092634469.

The spelling of 261664156 in words is "two hundred sixty-one million, six hundred sixty-four thousand, one hundred fifty-six".