21643716 has 24 divisors (see below), whose sum is σ = 51456384. Its totient is φ = 7078240.

The previous prime is 21643693. The next prime is 21643723. The reversal of 21643716 is 61734612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16380 + ... + 17651.

It is an arithmetic number, because the mean of its divisors is an integer number (2144016).

Almost surely, 2^21643716 is an apocalyptic number.

It is an amenable number.

21643716 is an abundant number, since it is smaller than the sum of its proper divisors (29812668).

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

21643716 is a wasteful number, since it uses less digits than its factorization.

21643716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34091 (or 34089 counting only the distinct ones).

The product of its digits is 6048, while the sum is 30.

The square root of 21643716 is about 4652.2807309964. The cubic root of 21643716 is about 278.6830846102.

The spelling of 21643716 in words is "twenty-one million, six hundred forty-three thousand, seven hundred sixteen".