31351547561 has 2 divisors, whose sum is σ = 31351547562. Its totient is φ = 31351547560.

The previous prime is 31351547537. The next prime is 31351547567. The reversal of 31351547561 is 16574515313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17093993536 + 14257554025 = 130744^2 + 119405^2 .

It is a cyclic number.

It is not a de Polignac number, because 31351547561 - 2¹⁴ = 31351531177 is a prime.

It is not a weakly prime, because it can be changed into another prime (31351547567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15675773780 + 15675773781.

It is an arithmetic number, because the mean of its divisors is an integer number (15675773781).

Almost surely, 2^31351547561 is an apocalyptic number.

It is an amenable number.

31351547561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31351547561 is an equidigital number, since it uses as much as digits as its factorization.

31351547561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 41.

The spelling of 31351547561 in words is "thirty-one billion, three hundred fifty-one million, five hundred forty-seven thousand, five hundred sixty-one".