31681418693 has 2 divisors, whose sum is σ = 31681418694. Its totient is φ = 31681418692.

The previous prime is 31681418651. The next prime is 31681418777. The reversal of 31681418693 is 39681418613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21508275649 + 10173143044 = 146657^2 + 100862^2 .

It is a cyclic number.

It is not a de Polignac number, because 31681418693 - 2⁸ = 31681418437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31681417693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15840709346 + 15840709347.

It is an arithmetic number, because the mean of its divisors is an integer number (15840709347).

Almost surely, 2^31681418693 is an apocalyptic number.

It is an amenable number.

31681418693 is a deficient number, since it is larger than the sum of its proper divisors (1).

31681418693 is an equidigital number, since it uses as much as digits as its factorization.

31681418693 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 50.

The spelling of 31681418693 in words is "thirty-one billion, six hundred eighty-one million, four hundred eighteen thousand, six hundred ninety-three".