31213112121 has 12 divisors (see below), whose sum is σ = 45355582272. Its totient is φ = 20684137176.

The previous prime is 31213112107. The next prime is 31213112129. The reversal of 31213112121 is 12121131213.

31213112121 is a `hidden beast` number, since 312 + 1 + 311 + 21 + 21 = 666.

It is not a de Polignac number, because 31213112121 - 2²⁶ = 31146003257 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31213112094 and 31213112103.

It is not an unprimeable number, because it can be changed into a prime (31213112129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10382101 + ... + 10385106.

It is an arithmetic number, because the mean of its divisors is an integer number (3779631856).

Almost surely, 2^31213112121 is an apocalyptic number.

It is an amenable number.

31213112121 is a deficient number, since it is larger than the sum of its proper divisors (14142470151).

31213112121 is a wasteful number, since it uses less digits than its factorization.

31213112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20767380 (or 20767377 counting only the distinct ones).

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

Adding to 31213112121 its reverse (12121131213), we get a palindrome (43334243334).

The spelling of 31213112121 in words is "thirty-one billion, two hundred thirteen million, one hundred twelve thousand, one hundred twenty-one".