21660964 has 24 divisors (see below), whose sum is σ = 41404608. Its totient is φ = 9854880.

The previous prime is 21660959. The next prime is 21660967. The reversal of 21660964 is 46906612.

It is a super-2 number, since 2×21660964² = 938394722818592, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21660967) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 759 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (1725192).

Almost surely, 2^21660964 is an apocalyptic number.

It is an amenable number.

21660964 is a deficient number, since it is larger than the sum of its proper divisors (19743644).

21660964 is a wasteful number, since it uses less digits than its factorization.

21660964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5955 (or 5953 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 21660964 is about 4654.1340762810. The cubic root of 21660964 is about 278.7570929979.

The spelling of 21660964 in words is "twenty-one million, six hundred sixty thousand, nine hundred sixty-four".