3131231021 has 4 divisors (see below), whose sum is σ = 3132547392. Its totient is φ = 3129914652.

The previous prime is 3131231011. The next prime is 3131231023. The reversal of 3131231021 is 1201321313.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1201321313 = 32797 ⋅36629.

It is a cyclic number.

It is not a de Polignac number, because 3131231021 - 2¹⁸ = 3130968877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3131231023) 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 3 ways as a sum of consecutive naturals, for example, 654611 + ... + 659376.

It is an arithmetic number, because the mean of its divisors is an integer number (783136848).

Almost surely, 2^3131231021 is an apocalyptic number.

It is an amenable number.

3131231021 is a deficient number, since it is larger than the sum of its proper divisors (1316371).

3131231021 is a wasteful number, since it uses less digits than its factorization.

3131231021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1316370.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 3131231021 is about 55957.4036299041. The cubic root of 3131231021 is about 1462.9799368292.

Adding to 3131231021 its reverse (1201321313), we get a palindrome (4332552334).

The spelling of 3131231021 in words is "three billion, one hundred thirty-one million, two hundred thirty-one thousand, twenty-one".