21838788 has 48 divisors (see below), whose sum is σ = 56871360. Its totient is φ = 7247232.

The previous prime is 21838763. The next prime is 21838801. The reversal of 21838788 is 88783812.

It is a happy number.

It is a super-2 number, since 2×21838788² = 953865322617888, which contains 22 as substring.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 46531 + ... + 46997.

It is an arithmetic number, because the mean of its divisors is an integer number (1184820).

Almost surely, 2^21838788 is an apocalyptic number.

It is an amenable number.

21838788 is an abundant number, since it is smaller than the sum of its proper divisors (35032572).

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

21838788 is a wasteful number, since it uses less digits than its factorization.

21838788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913 (or 905 counting only the distinct ones).

The product of its digits is 172032, while the sum is 45.

The square root of 21838788 is about 4673.1989043909. The cubic root of 21838788 is about 279.5178266136.

The spelling of 21838788 in words is "twenty-one million, eight hundred thirty-eight thousand, seven hundred eighty-eight".