31231131977 has 2 divisors, whose sum is σ = 31231131978. Its totient is φ = 31231131976.

The previous prime is 31231131961. The next prime is 31231132103. The reversal of 31231131977 is 77913113213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24881592121 + 6349539856 = 157739^2 + 79684^2 .

It is a cyclic number.

It is not a de Polignac number, because 31231131977 - 2⁴ = 31231131961 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31231131977.

It is not a weakly prime, because it can be changed into another prime (31231131077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15615565988 + 15615565989.

It is an arithmetic number, because the mean of its divisors is an integer number (15615565989).

Almost surely, 2^31231131977 is an apocalyptic number.

It is an amenable number.

31231131977 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231131977 is an equidigital number, since it uses as much as digits as its factorization.

31231131977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23814, while the sum is 38.

The spelling of 31231131977 in words is "thirty-one billion, two hundred thirty-one million, one hundred thirty-one thousand, nine hundred seventy-seven".