21392188 has 12 divisors (see below), whose sum is σ = 39638592. Its totient is φ = 10066880.

The previous prime is 21392159. The next prime is 21392197. The reversal of 21392188 is 88129312.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a plaindrome in base 13.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 157228 + ... + 157363.

It is an arithmetic number, because the mean of its divisors is an integer number (3303216).

Almost surely, 2^21392188 is an apocalyptic number.

It is an amenable number.

21392188 is a deficient number, since it is larger than the sum of its proper divisors (18246404).

21392188 is a wasteful number, since it uses less digits than its factorization.

21392188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314612 (or 314610 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 21392188 is about 4625.1689698864. The cubic root of 21392188 is about 277.5993227234.

The spelling of 21392188 in words is "twenty-one million, three hundred ninety-two thousand, one hundred eighty-eight".