21818768 has 10 divisors (see below), whose sum is σ = 42273894. Its totient is φ = 10909376.

The previous prime is 21818747. The next prime is 21818779. The reversal of 21818768 is 86781812.

It can be written as a sum of positive squares in only one way, i.e., 15904144 + 5914624 = 3988^2 + 2432^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 681821 + ... + 681852.

Almost surely, 2^21818768 is an apocalyptic number.

It is an amenable number.

21818768 is a deficient number, since it is larger than the sum of its proper divisors (20455126).

21818768 is a wasteful number, since it uses less digits than its factorization.

21818768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1363681 (or 1363675 counting only the distinct ones).

The product of its digits is 43008, while the sum is 41.

The square root of 21818768 is about 4671.0564115626. The cubic root of 21818768 is about 279.4323875357.

The spelling of 21818768 in words is "twenty-one million, eight hundred eighteen thousand, seven hundred sixty-eight".