13131031221 has 72 divisors (see below), whose sum is σ = 24582040704. Its totient is φ = 6676064640.

The previous prime is 13131031211. The next prime is 13131031231. The reversal of 13131031221 is 12213013131.

13131031221 is a `hidden beast` number, since 131 + 310 + 3 + 1 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (13131031211) and next prime (13131031231).

It is not a de Polignac number, because 13131031221 - 2⁵ = 13131031189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13131031194 and 13131031203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13131031211) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 199201 + ... + 256793.

It is an arithmetic number, because the mean of its divisors is an integer number (341417232).

Almost surely, 2^13131031221 is an apocalyptic number.

13131031221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13131031221 is a deficient number, since it is larger than the sum of its proper divisors (11451009483).

13131031221 is a wasteful number, since it uses less digits than its factorization.

13131031221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57671 (or 57661 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 13131031221 its reverse (12213013131), we get a palindrome (25344044352).

The spelling of 13131031221 in words is "thirteen billion, one hundred thirty-one million, thirty-one thousand, two hundred twenty-one".