23531510521 has 4 divisors (see below), whose sum is σ = 24105449844. Its totient is φ = 22957571200.

The previous prime is 23531510479. The next prime is 23531510557. The reversal of 23531510521 is 12501513532.

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 2697763600 + 20833746921 = 51940^2 + 144339^2 .

It is a cyclic number.

It is not a de Polignac number, because 23531510521 - 2¹⁷ = 23531379449 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 23531510521.

It is not an unprimeable number, because it can be changed into a prime (23531510221) 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, 286969600 + ... + 286969681.

It is an arithmetic number, because the mean of its divisors is an integer number (6026362461).

Almost surely, 2^23531510521 is an apocalyptic number.

It is an amenable number.

23531510521 is a deficient number, since it is larger than the sum of its proper divisors (573939323).

23531510521 is an equidigital number, since it uses as much as digits as its factorization.

23531510521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573939322.

The product of its (nonzero) digits is 4500, while the sum is 28.

The spelling of 23531510521 in words is "twenty-three billion, five hundred thirty-one million, five hundred ten thousand, five hundred twenty-one".