21626985 has 16 divisors (see below), whose sum is σ = 34675200. Its totient is φ = 11510400.

The previous prime is 21626977. The next prime is 21626987. The reversal of 21626985 is 58962612.

It is not a de Polignac number, because 21626985 - 2³ = 21626977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21626987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7816 + ... + 10214.

It is an arithmetic number, because the mean of its divisors is an integer number (2167200).

Almost surely, 2^21626985 is an apocalyptic number.

It is an amenable number.

21626985 is a deficient number, since it is larger than the sum of its proper divisors (13048215).

21626985 is a wasteful number, since it uses less digits than its factorization.

21626985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3008.

The product of its digits is 51840, while the sum is 39.

The square root of 21626985 is about 4650.4822330593. The cubic root of 21626985 is about 278.6112570084.

The spelling of 21626985 in words is "twenty-one million, six hundred twenty-six thousand, nine hundred eighty-five".