256615506 has 64 divisors (see below), whose sum is σ = 664070400. Its totient is φ = 71929728.

The previous prime is 256615487. The next prime is 256615523. The reversal of 256615506 is 605516652.

It is a happy number.

256615506 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13630 + ... + 26438.

It is an arithmetic number, because the mean of its divisors is an integer number (10376100).

Almost surely, 2^256615506 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256615506, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332035200).

256615506 is an abundant number, since it is smaller than the sum of its proper divisors (407454894).

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

256615506 is a wasteful number, since it uses less digits than its factorization.

256615506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12880 (or 12874 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 256615506 is about 16019.2230148656. The cubic root of 256615506 is about 635.4688962379.

The spelling of 256615506 in words is "two hundred fifty-six million, six hundred fifteen thousand, five hundred six".