13123431021 has 4 divisors (see below), whose sum is σ = 17497908032. Its totient is φ = 8748954012.

The previous prime is 13123431019. The next prime is 13123431029. The reversal of 13123431021 is 12013432131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 13123431021 - 2¹ = 13123431019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13123431029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2187238501 + ... + 2187238506.

It is an arithmetic number, because the mean of its divisors is an integer number (4374477008).

Almost surely, 2^13123431021 is an apocalyptic number.

It is an amenable number.

13123431021 is a deficient number, since it is larger than the sum of its proper divisors (4374477011).

13123431021 is an equidigital number, since it uses as much as digits as its factorization.

13123431021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4374477010.

The product of its (nonzero) digits is 432, while the sum is 21.

Adding to 13123431021 its reverse (12013432131), we get a palindrome (25136863152).

The spelling of 13123431021 in words is "thirteen billion, one hundred twenty-three million, four hundred thirty-one thousand, twenty-one".