13831393921 has 4 divisors (see below), whose sum is σ = 13907810644. Its totient is φ = 13754977200.

The previous prime is 13831393913. The next prime is 13831393931. The reversal of 13831393921 is 12939313831.

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 683561025 + 13147832896 = 26145^2 + 114664^2 .

It is a cyclic number.

It is not a de Polignac number, because 13831393921 - 2³ = 13831393913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13831393931) 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, 38208090 + ... + 38208451.

It is an arithmetic number, because the mean of its divisors is an integer number (3476952661).

Almost surely, 2^13831393921 is an apocalyptic number.

It is an amenable number.

13831393921 is a deficient number, since it is larger than the sum of its proper divisors (76416723).

13831393921 is an equidigital number, since it uses as much as digits as its factorization.

13831393921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76416722.

The product of its digits is 104976, while the sum is 43.

The spelling of 13831393921 in words is "thirteen billion, eight hundred thirty-one million, three hundred ninety-three thousand, nine hundred twenty-one".