256115720 has 64 divisors (see below), whose sum is σ = 662169600. Its totient is φ = 87333120.

The previous prime is 256115719. The next prime is 256115749. The reversal of 256115720 is 27511652.

It is a super-2 number, since 2×256115720² = 131190524062236800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51086 + ... + 55874.

It is an arithmetic number, because the mean of its divisors is an integer number (10346400).

Almost surely, 2^256115720 is an apocalyptic number.

256115720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256115720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331084800).

256115720 is an abundant number, since it is smaller than the sum of its proper divisors (406053880).

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

256115720 is a wasteful number, since it uses less digits than its factorization.

256115720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4998 (or 4994 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 256115720 is about 16003.6158414278. The cubic root of 256115720 is about 635.0560803593.

It can be divided in two parts, 2561 and 15720, that added together give a palindrome (18281).

The spelling of 256115720 in words is "two hundred fifty-six million, one hundred fifteen thousand, seven hundred twenty".