3131220121 has 4 divisors (see below), whose sum is σ = 3296021200. Its totient is φ = 2966419044.

The previous prime is 3131220119. The next prime is 3131220133. The reversal of 3131220121 is 1210221313.

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 a cyclic number.

It is not a de Polignac number, because 3131220121 - 2¹ = 3131220119 is a prime.

It is a super-3 number, since 3×3131220121³ (a number of 29 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 3131220095 and 3131220104.

It is not an unprimeable number, because it can be changed into a prime (3131220721) 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, 82400511 + ... + 82400548.

It is an arithmetic number, because the mean of its divisors is an integer number (824005300).

Almost surely, 2^3131220121 is an apocalyptic number.

It is an amenable number.

3131220121 is a deficient number, since it is larger than the sum of its proper divisors (164801079).

3131220121 is a wasteful number, since it uses less digits than its factorization.

3131220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164801078.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 3131220121 is about 55957.3062343069. The cubic root of 3131220121 is about 1462.9782392540.

Adding to 3131220121 its reverse (1210221313), we get a palindrome (4341441434).

The spelling of 3131220121 in words is "three billion, one hundred thirty-one million, two hundred twenty thousand, one hundred twenty-one".