312131021 has 2 divisors, whose sum is σ = 312131022. Its totient is φ = 312131020.

The previous prime is 312130979. The next prime is 312131041. The reversal of 312131021 is 120131213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 311346025 + 784996 = 17645^2 + 886^2 .

It is an emirp because it is prime and its reverse (120131213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 312131021 - 2¹⁸ = 311868877 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 312130987 and 312131005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312131041) 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 as a sum of consecutive naturals, namely, 156065510 + 156065511.

It is an arithmetic number, because the mean of its divisors is an integer number (156065511).

Almost surely, 2^312131021 is an apocalyptic number.

It is an amenable number.

312131021 is a deficient number, since it is larger than the sum of its proper divisors (1).

312131021 is an equidigital number, since it uses as much as digits as its factorization.

312131021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 312131021 is about 17667.2301451020. The cubic root of 312131021 is about 678.3372154689.

Adding to 312131021 its reverse (120131213), we get a palindrome (432262234).

The spelling of 312131021 in words is "three hundred twelve million, one hundred thirty-one thousand, twenty-one".