31691357377 has 2 divisors, whose sum is σ = 31691357378. Its totient is φ = 31691357376.

The previous prime is 31691357371. The next prime is 31691357419. The reversal of 31691357377 is 77375319613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31628488336 + 62869041 = 177844^2 + 7929^2 .

It is a cyclic number.

It is not a de Polignac number, because 31691357377 - 2²³ = 31682968769 is a prime.

It is not a weakly prime, because it can be changed into another prime (31691357371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15845678688 + 15845678689.

It is an arithmetic number, because the mean of its divisors is an integer number (15845678689).

Almost surely, 2^31691357377 is an apocalyptic number.

It is an amenable number.

31691357377 is a deficient number, since it is larger than the sum of its proper divisors (1).

31691357377 is an equidigital number, since it uses as much as digits as its factorization.

31691357377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2500470, while the sum is 52.

The spelling of 31691357377 in words is "thirty-one billion, six hundred ninety-one million, three hundred fifty-seven thousand, three hundred seventy-seven".