3131000021 has 2 divisors, whose sum is σ = 3131000022. Its totient is φ = 3131000020.

The previous prime is 3131000017. The next prime is 3131000029. The reversal of 3131000021 is 1200001313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2179956100 + 951043921 = 46690^2 + 30839^2 .

It is a cyclic number.

It is not a de Polignac number, because 3131000021 - 2² = 3131000017 is a prime.

It is a super-2 number, since 2×3131000021² = 19606322263004000882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 3130999966 and 3131000011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3131000029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1565500010 + 1565500011.

It is an arithmetic number, because the mean of its divisors is an integer number (1565500011).

Almost surely, 2^3131000021 is an apocalyptic number.

It is an amenable number.

3131000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3131000021 is an equidigital number, since it uses as much as digits as its factorization.

3131000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 3131000021 is about 55955.3395218008. The cubic root of 3131000021 is about 1462.9439598525.

Adding to 3131000021 its reverse (1200001313), we get a palindrome (4331001334).

The spelling of 3131000021 in words is "three billion, one hundred thirty-one million, twenty-one", and thus it is an aban number.