21216523512 has 32 divisors (see below), whose sum is σ = 55347454080. Its totient is φ = 6764688480.

The previous prime is 21216523501. The next prime is 21216523513. The reversal of 21216523512 is 21532561212.

It is a self number, because there is not a number n which added to its sum of digits gives 21216523512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216523513) 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, 19217314 + ... + 19218417.

It is an arithmetic number, because the mean of its divisors is an integer number (1729607940).

Almost surely, 2^21216523512 is an apocalyptic number.

It is an amenable number.

21216523512 is an abundant number, since it is smaller than the sum of its proper divisors (34130930568).

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

21216523512 is a wasteful number, since it uses less digits than its factorization.

21216523512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38435763 (or 38435759 counting only the distinct ones).

The product of its digits is 7200, while the sum is 30.

The spelling of 21216523512 in words is "twenty-one billion, two hundred sixteen million, five hundred twenty-three thousand, five hundred twelve".