256215564 has 108 divisors (see below), whose sum is σ = 718918200. Its totient is φ = 76876800.

The previous prime is 256215563. The next prime is 256215577. The reversal of 256215564 is 465512652.

256215564 is a `hidden beast` number, since 25 + 62 + 15 + 564 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (256215563) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 570412 + ... + 570860.

It is an arithmetic number, because the mean of its divisors is an integer number (6656650).

Almost surely, 2^256215564 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 256215564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (359459100).

256215564 is an abundant number, since it is smaller than the sum of its proper divisors (462702636).

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

256215564 is a wasteful number, since it uses less digits than its factorization.

256215564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612 (or 596 counting only the distinct ones).

The product of its digits is 72000, while the sum is 36.

The square root of 256215564 is about 16006.7349575109. The cubic root of 256215564 is about 635.1385929329.

The spelling of 256215564 in words is "two hundred fifty-six million, two hundred fifteen thousand, five hundred sixty-four".