21646966 has 16 divisors (see below), whose sum is σ = 37287360. Its totient is φ = 9321480.

The previous prime is 21646943. The next prime is 21646973. The reversal of 21646966 is 66964612.

It is a super-2 number, since 2×21646966² = 937182274010312, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 25476 + ... + 26311.

It is an arithmetic number, because the mean of its divisors is an integer number (2330460).

Almost surely, 2^21646966 is an apocalyptic number.

21646966 is a deficient number, since it is larger than the sum of its proper divisors (15640394).

21646966 is a wasteful number, since it uses less digits than its factorization.

21646966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51819.

The product of its digits is 93312, while the sum is 40.

The square root of 21646966 is about 4652.6300089304. The cubic root of 21646966 is about 278.6970328419.

The spelling of 21646966 in words is "twenty-one million, six hundred forty-six thousand, nine hundred sixty-six".