21875564 has 6 divisors (see below), whose sum is σ = 38282244. Its totient is φ = 10937780.

The previous prime is 21875561. The next prime is 21875573. The reversal of 21875564 is 46557812.

It is not an unprimeable number, because it can be changed into a prime (21875561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2734442 + ... + 2734449.

It is an arithmetic number, because the mean of its divisors is an integer number (6380374).

Almost surely, 2^21875564 is an apocalyptic number.

It is an amenable number.

21875564 is a deficient number, since it is larger than the sum of its proper divisors (16406680).

21875564 is a wasteful number, since it uses less digits than its factorization.

21875564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5468895 (or 5468893 counting only the distinct ones).

The product of its digits is 67200, while the sum is 38.

The square root of 21875564 is about 4677.1320272150. The cubic root of 21875564 is about 279.6746390828.

The spelling of 21875564 in words is "twenty-one million, eight hundred seventy-five thousand, five hundred sixty-four".