31666511545661 has 2 divisors, whose sum is σ = 31666511545662. Its totient is φ = 31666511545660.

The previous prime is 31666511545633. The next prime is 31666511545717. The reversal of 31666511545661 is 16654511566613.

It is an a-pointer prime, because the next prime (31666511545717) can be obtained adding 31666511545661 to its sum of digits (56).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16110831268900 + 15555680276761 = 4013830^2 + 3944069^2 .

It is a cyclic number.

It is not a de Polignac number, because 31666511545661 - 2⁶ = 31666511545597 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31666511545597 and 31666511545606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31666511545631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15833255772830 + 15833255772831.

It is an arithmetic number, because the mean of its divisors is an integer number (15833255772831).

Almost surely, 2^{31666511545661} is an apocalyptic number.

It is an amenable number.

31666511545661 is a deficient number, since it is larger than the sum of its proper divisors (1).

31666511545661 is an equidigital number, since it uses as much as digits as its factorization.

31666511545661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664000, while the sum is 56.

The spelling of 31666511545661 in words is "thirty-one trillion, six hundred sixty-six billion, five hundred eleven million, five hundred forty-five thousand, six hundred sixty-one".