31320375661 has 2 divisors, whose sum is σ = 31320375662. Its totient is φ = 31320375660.

The previous prime is 31320375617. The next prime is 31320375677. The reversal of 31320375661 is 16657302313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25739389225 + 5580986436 = 160435^2 + 74706^2 .

It is a cyclic number.

It is not a de Polignac number, because 31320375661 - 2¹¹ = 31320373613 is a prime.

It is a super-2 number, since 2×31320375661² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31320375661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31320375601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15660187830 + 15660187831.

It is an arithmetic number, because the mean of its divisors is an integer number (15660187831).

Almost surely, 2^31320375661 is an apocalyptic number.

It is an amenable number.

31320375661 is a deficient number, since it is larger than the sum of its proper divisors (1).

31320375661 is an equidigital number, since it uses as much as digits as its factorization.

31320375661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 37.

Adding to 31320375661 its reverse (16657302313), we get a palindrome (47977677974).

The spelling of 31320375661 in words is "thirty-one billion, three hundred twenty million, three hundred seventy-five thousand, six hundred sixty-one".