31121121213 has 160 divisors (see below), whose sum is σ = 61208421120. Its totient is φ = 15290726400.

The previous prime is 31121121211. The next prime is 31121121223. The reversal of 31121121213 is 31212112113.

31121121213 is a `hidden beast` number, since 311 + 21 + 121 + 213 = 666.

It is not a de Polignac number, because 31121121213 - 2¹ = 31121121211 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121121211) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 12654778 + ... + 12657236.

It is an arithmetic number, because the mean of its divisors is an integer number (382552632).

Almost surely, 2^31121121213 is an apocalyptic number.

It is an amenable number.

31121121213 is a deficient number, since it is larger than the sum of its proper divisors (30087299907).

31121121213 is a wasteful number, since it uses less digits than its factorization.

31121121213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2609 (or 2600 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 31121121213 its reverse (31212112113), we get a palindrome (62333233326).

The spelling of 31121121213 in words is "thirty-one billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred thirteen".