21916812 has 48 divisors (see below), whose sum is σ = 52774400. Its totient is φ = 7076160.

The previous prime is 21916793. The next prime is 21916847. The reversal of 21916812 is 21861912.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21916812.

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, 57639 + ... + 58017.

Almost surely, 2^21916812 is an apocalyptic number.

It is an amenable number.

21916812 is an abundant number, since it is smaller than the sum of its proper divisors (30857588).

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

21916812 is a wasteful number, since it uses less digits than its factorization.

21916812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526 (or 524 counting only the distinct ones).

The product of its digits is 1728, while the sum is 30.

The square root of 21916812 is about 4681.5394903813. The cubic root of 21916812 is about 279.8503111466.

The spelling of 21916812 in words is "twenty-one million, nine hundred sixteen thousand, eight hundred twelve".