21788016 has 40 divisors (see below), whose sum is σ = 59598864. Its totient is φ = 6835200.

The previous prime is 21787981. The next prime is 21788017. The reversal of 21788016 is 61088712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21788017) 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, 12535 + ... + 14166.

Almost surely, 2^21788016 is an apocalyptic number.

It is an amenable number.

21788016 is an abundant number, since it is smaller than the sum of its proper divisors (37810848).

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

21788016 is a wasteful number, since it uses less digits than its factorization.

21788016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26729 (or 26723 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 21788016 is about 4667.7634901524. The cubic root of 21788016 is about 279.3010457925.

The spelling of 21788016 in words is "twenty-one million, seven hundred eighty-eight thousand, sixteen".