21788956 has 24 divisors (see below), whose sum is σ = 44295776. Its totient is φ = 9184320.

The previous prime is 21788933. The next prime is 21788959. The reversal of 21788956 is 65988712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21788959) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4671 + ... + 8086.

Almost surely, 2^21788956 is an apocalyptic number.

It is an amenable number.

21788956 is an abundant number, since it is smaller than the sum of its proper divisors (22506820).

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

21788956 is a wasteful number, since it uses less digits than its factorization.

21788956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12829 (or 12827 counting only the distinct ones).

The product of its digits is 241920, while the sum is 46.

The square root of 21788956 is about 4667.8641796865. The cubic root of 21788956 is about 279.3050623615.

The spelling of 21788956 in words is "twenty-one million, seven hundred eighty-eight thousand, nine hundred fifty-six".