31686342257 has 2 divisors, whose sum is σ = 31686342258. Its totient is φ = 31686342256.

The previous prime is 31686342221. The next prime is 31686342287. The reversal of 31686342257 is 75224368613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31627421281 + 58920976 = 177841^2 + 7676^2 .

It is an emirp because it is prime and its reverse (75224368613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31686342257 - 2¹⁴ = 31686325873 is a prime.

It is not a weakly prime, because it can be changed into another prime (31686342287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15843171128 + 15843171129.

It is an arithmetic number, because the mean of its divisors is an integer number (15843171129).

Almost surely, 2^31686342257 is an apocalyptic number.

It is an amenable number.

31686342257 is a deficient number, since it is larger than the sum of its proper divisors (1).

31686342257 is an equidigital number, since it uses as much as digits as its factorization.

31686342257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 47.

The spelling of 31686342257 in words is "thirty-one billion, six hundred eighty-six million, three hundred forty-two thousand, two hundred fifty-seven".