21523513752 has 160 divisors (see below), whose sum is σ = 65092288800. Its totient is φ = 6605369856.

The previous prime is 21523513721. The next prime is 21523513771. The reversal of 21523513752 is 25731532512.

21523513752 is a `hidden beast` number, since 2 + 1 + 523 + 51 + 37 + 52 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3442293 + ... + 3448539.

It is an arithmetic number, because the mean of its divisors is an integer number (406826805).

Almost surely, 2^21523513752 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 21523513752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32546144400).

21523513752 is an abundant number, since it is smaller than the sum of its proper divisors (43568775048).

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

21523513752 is a wasteful number, since it uses less digits than its factorization.

21523513752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6687 (or 6674 counting only the distinct ones).

The product of its digits is 63000, while the sum is 36.

The spelling of 21523513752 in words is "twenty-one billion, five hundred twenty-three million, five hundred thirteen thousand, seven hundred fifty-two".