3131861 has 2 divisors, whose sum is σ = 3131862. Its totient is φ = 3131860.

The previous prime is 3131857. The next prime is 3131879. The reversal of 3131861 is 1681313.

3131861 is nontrivially palindromic in base 9.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3129361 + 2500 = 1769^2 + 50^2 .

It is a cyclic number.

It is not a de Polignac number, because 3131861 - 2² = 3131857 is a prime.

It is a Chen prime.

It is equal to p₂₂₅₆₄₄ and since 3131861 and 225644 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3131851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1565930 + 1565931.

It is an arithmetic number, because the mean of its divisors is an integer number (1565931).

Almost surely, 2^3131861 is an apocalyptic number.

It is an amenable number.

3131861 is a deficient number, since it is larger than the sum of its proper divisors (1).

3131861 is an equidigital number, since it uses as much as digits as its factorization.

3131861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 23.

The square root of 3131861 is about 1769.7064728367. The cubic root of 3131861 is about 146.3078043594.

The spelling of 3131861 in words is "three million, one hundred thirty-one thousand, eight hundred sixty-one".