21713985 has 24 divisors (see below), whose sum is σ = 37752000. Its totient is φ = 11545632.

The previous prime is 21713983. The next prime is 21714013. The reversal of 21713985 is 58931712.

It is not a de Polignac number, because 21713985 - 2¹ = 21713983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21713983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21972 + ... + 22938.

It is an arithmetic number, because the mean of its divisors is an integer number (1573000).

Almost surely, 2^21713985 is an apocalyptic number.

It is an amenable number.

21713985 is a deficient number, since it is larger than the sum of its proper divisors (16038015).

21713985 is a wasteful number, since it uses less digits than its factorization.

21713985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1477 (or 1474 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21713985 is about 4659.8267135163. The cubic root of 21713985 is about 278.9843518414.

The spelling of 21713985 in words is "twenty-one million, seven hundred thirteen thousand, nine hundred eighty-five".