261510256 has 90 divisors (see below), whose sum is σ = 606194088. Its totient is φ = 108964800.

The previous prime is 261510241. The next prime is 261510289. The reversal of 261510256 is 652015162.

261510256 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×261510256² = 136775227986371072, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1731781 + ... + 1731931.

Almost surely, 2^261510256 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 261510256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (303097044).

261510256 is an abundant number, since it is smaller than the sum of its proper divisors (344683832).

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

261510256 is a wasteful number, since it uses less digits than its factorization.

261510256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 261510256 is about 16171.2787373170. The cubic root of 261510256 is about 639.4838416440.

The spelling of 261510256 in words is "two hundred sixty-one million, five hundred ten thousand, two hundred fifty-six".