21992866 has 48 divisors (see below), whose sum is σ = 41713056. Its totient is φ = 8636544.

The previous prime is 21992863. The next prime is 21992897. The reversal of 21992866 is 66829912.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is not an unprimeable number, because it can be changed into a prime (21992863) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 71485 + ... + 71791.

It is an arithmetic number, because the mean of its divisors is an integer number (869022).

Almost surely, 2^21992866 is an apocalyptic number.

21992866 is a deficient number, since it is larger than the sum of its proper divisors (19720190).

21992866 is a wasteful number, since it uses less digits than its factorization.

21992866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383 (or 376 counting only the distinct ones).

The product of its digits is 93312, while the sum is 43.

The square root of 21992866 is about 4689.6552112069. The cubic root of 21992866 is about 280.1736422933.

The spelling of 21992866 in words is "twenty-one million, nine hundred ninety-two thousand, eight hundred sixty-six".