21903788 has 12 divisors (see below), whose sum is σ = 38425632. Its totient is φ = 10925040.

The previous prime is 21903781. The next prime is 21903793. The reversal of 21903788 is 88730912.

It is not an unprimeable number, because it can be changed into a prime (21903781) 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 3 ways as a sum of consecutive naturals, for example, 4820 + ... + 8187.

It is an arithmetic number, because the mean of its divisors is an integer number (3202136).

Almost surely, 2^21903788 is an apocalyptic number.

It is an amenable number.

21903788 is a deficient number, since it is larger than the sum of its proper divisors (16521844).

21903788 is a wasteful number, since it uses less digits than its factorization.

21903788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13432 (or 13430 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 21903788 is about 4680.1482882490. The cubic root of 21903788 is about 279.7948667591.

The spelling of 21903788 in words is "twenty-one million, nine hundred three thousand, seven hundred eighty-eight".