21192788 has 6 divisors (see below), whose sum is σ = 37087386. Its totient is φ = 10596392.

The previous prime is 21192763. The next prime is 21192791. The reversal of 21192788 is 88729112.

It can be written as a sum of positive squares in only one way, i.e., 10837264 + 10355524 = 3292^2 + 3218^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2649095 + ... + 2649102.

It is an arithmetic number, because the mean of its divisors is an integer number (6181231).

Almost surely, 2^21192788 is an apocalyptic number.

It is an amenable number.

21192788 is a deficient number, since it is larger than the sum of its proper divisors (15894598).

21192788 is a wasteful number, since it uses less digits than its factorization.

21192788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5298201 (or 5298199 counting only the distinct ones).

The product of its digits is 16128, while the sum is 38.

The square root of 21192788 is about 4603.5625335168. The cubic root of 21192788 is about 276.7341130060.

The spelling of 21192788 in words is "twenty-one million, one hundred ninety-two thousand, seven hundred eighty-eight".