31140665561 has 2 divisors, whose sum is σ = 31140665562. Its totient is φ = 31140665560.

The previous prime is 31140665527. The next prime is 31140665597. The reversal of 31140665561 is 16556604113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15670032400 + 15470633161 = 125180^2 + 124381^2 .

It is a cyclic number.

It is not a de Polignac number, because 31140665561 - 2¹⁰ = 31140664537 is a prime.

It is not a weakly prime, because it can be changed into another prime (31140662561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15570332780 + 15570332781.

It is an arithmetic number, because the mean of its divisors is an integer number (15570332781).

Almost surely, 2^31140665561 is an apocalyptic number.

It is an amenable number.

31140665561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31140665561 is an equidigital number, since it uses as much as digits as its factorization.

31140665561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64800, while the sum is 38.

The spelling of 31140665561 in words is "thirty-one billion, one hundred forty million, six hundred sixty-five thousand, five hundred sixty-one".