21664058 has 16 divisors (see below), whose sum is σ = 35085960. Its totient is φ = 9973056.

The previous prime is 21664051. The next prime is 21664063. The reversal of 21664058 is 85046612.

It can be written as a sum of positive squares in 4 ways, for example, as 12159169 + 9504889 = 3487^2 + 3083^2 .

It is not an unprimeable number, because it can be changed into a prime (21664051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12416 + ... + 14052.

Almost surely, 2^21664058 is an apocalyptic number.

21664058 is a deficient number, since it is larger than the sum of its proper divisors (13421902).

21664058 is a wasteful number, since it uses less digits than its factorization.

21664058 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2161.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 21664058 is about 4654.4664570711. The cubic root of 21664058 is about 278.7703646969.

The spelling of 21664058 in words is "twenty-one million, six hundred sixty-four thousand, fifty-eight".