261320256 has 112 divisors (see below), whose sum is σ = 778134080. Its totient is φ = 87060096.

The previous prime is 261320251. The next prime is 261320261. The reversal of 261320256 is 652023162.

261320256 is a `hidden beast` number, since 2 + 613 + 20 + 25 + 6 = 666.

261320256 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261320251) and next prime (261320261).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (261320251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139035 + ... + 140901.

Almost surely, 2^261320256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261320256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (389067040).

261320256 is an abundant number, since it is smaller than the sum of its proper divisors (516813824).

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

261320256 is an frugal number, since it uses more digits than its factorization.

261320256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1900 (or 1872 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 261320256 is about 16165.4030571465. The cubic root of 261320256 is about 639.3289320185.

The spelling of 261320256 in words is "two hundred sixty-one million, three hundred twenty thousand, two hundred fifty-six".