21867788 has 12 divisors (see below), whose sum is σ = 38464272. Its totient is φ = 10878000.

The previous prime is 21867773. The next prime is 21867821. The reversal of 21867788 is 88776812.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13088 + ... + 14663.

It is an arithmetic number, because the mean of its divisors is an integer number (3205356).

Almost surely, 2^21867788 is an apocalyptic number.

It is an amenable number.

21867788 is a deficient number, since it is larger than the sum of its proper divisors (16596484).

21867788 is a wasteful number, since it uses less digits than its factorization.

21867788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27952 (or 27950 counting only the distinct ones).

The product of its digits is 301056, while the sum is 47.

The square root of 21867788 is about 4676.3006746787. The cubic root of 21867788 is about 279.6414969624.

The spelling of 21867788 in words is "twenty-one million, eight hundred sixty-seven thousand, seven hundred eighty-eight".