23728013521 has 9 divisors (see below), whose sum is σ = 24523059483. Its totient is φ = 22957972560.

The previous prime is 23728013501. The next prime is 23728013579. The reversal of 23728013521 is 12531082732.

The square root of 23728013521 is 154039.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 4783243921 + 18944769600 = 69161^2 + 137640^2 .

It is not a de Polignac number, because 23728013521 - 2³³ = 15138078929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23728013501) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4772725 + ... + 4777693.

It is an arithmetic number, because the mean of its divisors is an integer number (2724784387).

Almost surely, 2^23728013521 is an apocalyptic number.

23728013521 is the 154039-th square number.

23728013521 is the 77020-th centered octagonal number.

It is an amenable number.

23728013521 is a deficient number, since it is larger than the sum of its proper divisors (795045962).

23728013521 is an frugal number, since it uses more digits than its factorization.

23728013521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10000 (or 5000 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 34.

The spelling of 23728013521 in words is "twenty-three billion, seven hundred twenty-eight million, thirteen thousand, five hundred twenty-one".