21819992 has 16 divisors (see below), whose sum is σ = 41474040. Its totient is φ = 10760256.

The previous prime is 21819991. The next prime is 21820013. The reversal of 21819992 is 29991812.

It is a super-2 number, since 2×21819992² = 952224101760128, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21819991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18098 + ... + 19265.

Almost surely, 2^21819992 is an apocalyptic number.

It is an amenable number.

21819992 is a deficient number, since it is larger than the sum of its proper divisors (19654048).

21819992 is a wasteful number, since it uses less digits than its factorization.

21819992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37442 (or 37438 counting only the distinct ones).

The product of its digits is 23328, while the sum is 41.

The square root of 21819992 is about 4671.1874293374. The cubic root of 21819992 is about 279.4376126832.

The spelling of 21819992 in words is "twenty-one million, eight hundred nineteen thousand, nine hundred ninety-two".