21854564 has 12 divisors (see below), whose sum is σ = 38706864. Its totient is φ = 10795464.

The previous prime is 21854563. The next prime is 21854587. The reversal of 21854564 is 46545812.

It is not an unprimeable number, because it can be changed into a prime (21854561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32582 + ... + 33245.

It is an arithmetic number, because the mean of its divisors is an integer number (3225572).

Almost surely, 2^21854564 is an apocalyptic number.

It is an amenable number.

21854564 is a deficient number, since it is larger than the sum of its proper divisors (16852300).

21854564 is a wasteful number, since it uses less digits than its factorization.

21854564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65914 (or 65912 counting only the distinct ones).

The product of its digits is 38400, while the sum is 35.

The square root of 21854564 is about 4674.8865226869. The cubic root of 21854564 is about 279.5851168532.

The spelling of 21854564 in words is "twenty-one million, eight hundred fifty-four thousand, five hundred sixty-four".