21715312 has 20 divisors (see below), whose sum is σ = 43903440. Its totient is φ = 10385408.

The previous prime is 21715297. The next prime is 21715313. The reversal of 21715312 is 21351712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29137 + ... + 29872.

It is an arithmetic number, because the mean of its divisors is an integer number (2195172).

Almost surely, 2^21715312 is an apocalyptic number.

It is an amenable number.

21715312 is an abundant number, since it is smaller than the sum of its proper divisors (22188128).

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

21715312 is a wasteful number, since it uses less digits than its factorization.

21715312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59040 (or 59034 counting only the distinct ones).

The product of its digits is 420, while the sum is 22.

The square root of 21715312 is about 4659.9690986100. The cubic root of 21715312 is about 278.9900348869.

The spelling of 21715312 in words is "twenty-one million, seven hundred fifteen thousand, three hundred twelve".