21318884 has 48 divisors (see below), whose sum is σ = 42311808. Its totient is φ = 9343488.

The previous prime is 21318881. The next prime is 21318889. The reversal of 21318884 is 48881312.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21318881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67094 + ... + 67410.

It is an arithmetic number, because the mean of its divisors is an integer number (881496).

Almost surely, 2^21318884 is an apocalyptic number.

It is an amenable number.

21318884 is a deficient number, since it is larger than the sum of its proper divisors (20992924).

21318884 is a wasteful number, since it uses less digits than its factorization.

21318884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404 (or 402 counting only the distinct ones).

The product of its digits is 12288, while the sum is 35.

The square root of 21318884 is about 4617.2377023498. The cubic root of 21318884 is about 277.2818792969.

The spelling of 21318884 in words is "twenty-one million, three hundred eighteen thousand, eight hundred eighty-four".