21666792 has 32 divisors (see below), whose sum is σ = 61905600. Its totient is φ = 6190464.

The previous prime is 21666791. The next prime is 21666811. The reversal of 21666792 is 29766612.

It is a self number, because there is not a number n which added to its sum of digits gives 21666792.

It is not an unprimeable number, because it can be changed into a prime (21666791) 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 7 ways as a sum of consecutive naturals, for example, 64317 + ... + 64652.

It is an arithmetic number, because the mean of its divisors is an integer number (1934550).

Almost surely, 2^21666792 is an apocalyptic number.

It is an amenable number.

21666792 is an abundant number, since it is smaller than the sum of its proper divisors (40238808).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21666792 is a wasteful number, since it uses less digits than its factorization.

21666792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128985 (or 128981 counting only the distinct ones).

The product of its digits is 54432, while the sum is 39.

The square root of 21666792 is about 4654.7601441965. The cubic root of 21666792 is about 278.7820911260.

The spelling of 21666792 in words is "twenty-one million, six hundred sixty-six thousand, seven hundred ninety-two".