21880564 has 24 divisors (see below), whose sum is σ = 40746888. Its totient is φ = 10245120.

The previous prime is 21880559. The next prime is 21880583. The reversal of 21880564 is 46508812.

It can be written as a sum of positive squares in 4 ways, for example, as 2696164 + 19184400 = 1642^2 + 4380^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15154 + ... + 16534.

It is an arithmetic number, because the mean of its divisors is an integer number (1697787).

Almost surely, 2^21880564 is an apocalyptic number.

It is an amenable number.

21880564 is a deficient number, since it is larger than the sum of its proper divisors (18866324).

21880564 is a wasteful number, since it uses less digits than its factorization.

21880564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1635 (or 1633 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 21880564 is about 4677.6665122687. Note that the first 3 decimals coincide. The cubic root of 21880564 is about 279.6959454541.

The spelling of 21880564 in words is "twenty-one million, eight hundred eighty thousand, five hundred sixty-four".