21512712 has 96 divisors (see below), whose sum is σ = 61447680. Its totient is φ = 6238080.

The previous prime is 21512669. The next prime is 21512713. The reversal of 21512712 is 21721512.

It is not an unprimeable number, because it can be changed into a prime (21512713) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 112537 + ... + 112727.

It is an arithmetic number, because the mean of its divisors is an integer number (640080).

Almost surely, 2^21512712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21512712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30723840).

21512712 is an abundant number, since it is smaller than the sum of its proper divisors (39934968).

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

21512712 is a wasteful number, since it uses less digits than its factorization.

21512712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 228 counting only the distinct ones).

The product of its digits is 280, while the sum is 21.

The square root of 21512712 is about 4638.1798154017. The cubic root of 21512712 is about 278.1196800228.

The spelling of 21512712 in words is "twenty-one million, five hundred twelve thousand, seven hundred twelve".