2561564 has 12 divisors (see below), whose sum is σ = 4513488. Its totient is φ = 1272000.

The previous prime is 2561551. The next prime is 2561593. The reversal of 2561564 is 4651652.

It is a super-2 number, since 2×2561564² = 13123220252192, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1517 + ... + 2724.

It is an arithmetic number, because the mean of its divisors is an integer number (376124).

2^2561564 is an apocalyptic number.

It is an amenable number.

2561564 is a deficient number, since it is larger than the sum of its proper divisors (1951924).

2561564 is a wasteful number, since it uses less digits than its factorization.

2561564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4396 (or 4394 counting only the distinct ones).

The product of its digits is 7200, while the sum is 29.

The square root of 2561564 is about 1600.4886753739. The cubic root of 2561564 is about 136.8259284210.

It can be divided in two parts, 2561 and 564, that added together give a 5-th power (3125 = 5⁵).

The spelling of 2561564 in words is "two million, five hundred sixty-one thousand, five hundred sixty-four".