31731603649 has 2 divisors, whose sum is σ = 31731603650. Its totient is φ = 31731603648.

The previous prime is 31731603613. The next prime is 31731603661. The reversal of 31731603649 is 94630613713.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25149202225 + 6582401424 = 158585^2 + 81132^2 .

It is a cyclic number.

It is not a de Polignac number, because 31731603649 - 2²⁵ = 31698049217 is a prime.

It is not a weakly prime, because it can be changed into another prime (31731603679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15865801824 + 15865801825.

It is an arithmetic number, because the mean of its divisors is an integer number (15865801825).

Almost surely, 2^31731603649 is an apocalyptic number.

It is an amenable number.

31731603649 is a deficient number, since it is larger than the sum of its proper divisors (1).

31731603649 is an equidigital number, since it uses as much as digits as its factorization.

31731603649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 43.

The spelling of 31731603649 in words is "thirty-one billion, seven hundred thirty-one million, six hundred three thousand, six hundred forty-nine".