21788382 has 32 divisors (see below), whose sum is σ = 54330624. Its totient is φ = 5659200.

The previous prime is 21788369. The next prime is 21788399. The reversal of 21788382 is 28388712.

It is a self number, because there is not a number n which added to its sum of digits gives 21788382.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23119 + ... + 24042.

It is an arithmetic number, because the mean of its divisors is an integer number (1697832).

Almost surely, 2^21788382 is an apocalyptic number.

21788382 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21788382 is an abundant number, since it is smaller than the sum of its proper divisors (32542242).

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

21788382 is a wasteful number, since it uses less digits than its factorization.

21788382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47184.

The product of its digits is 43008, while the sum is 39.

The square root of 21788382 is about 4667.8026950590. The cubic root of 21788382 is about 279.3026097044.

The spelling of 21788382 in words is "twenty-one million, seven hundred eighty-eight thousand, three hundred eighty-two".