23521031521 has 4 divisors (see below), whose sum is σ = 25330341652. Its totient is φ = 21711721392.

The previous prime is 23521031507. The next prime is 23521031531. The reversal of 23521031521 is 12513012532.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7584493921 + 15936537600 = 87089^2 + 126240^2 .

It is a cyclic number.

It is not a de Polignac number, because 23521031521 - 2⁷ = 23521031393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23521031531) 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, 904655046 + ... + 904655071.

It is an arithmetic number, because the mean of its divisors is an integer number (6332585413).

Almost surely, 2^23521031521 is an apocalyptic number.

It is an amenable number.

23521031521 is a deficient number, since it is larger than the sum of its proper divisors (1809310131).

23521031521 is a wasteful number, since it uses less digits than its factorization.

23521031521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1809310130.

The product of its (nonzero) digits is 1800, while the sum is 25.

The spelling of 23521031521 in words is "twenty-three billion, five hundred twenty-one million, thirty-one thousand, five hundred twenty-one".