18965971961 has 2 divisors, whose sum is σ = 18965971962. Its totient is φ = 18965971960.

The previous prime is 18965971951. The next prime is 18965971967. The reversal of 18965971961 is 16917956981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18866670736 + 99301225 = 137356^2 + 9965^2 .

It is a cyclic number.

It is not a de Polignac number, because 18965971961 - 2²⁶ = 18898863097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18965971894 and 18965971903.

It is not a weakly prime, because it can be changed into another prime (18965971967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9482985980 + 9482985981.

It is an arithmetic number, because the mean of its divisors is an integer number (9482985981).

Almost surely, 2^18965971961 is an apocalyptic number.

It is an amenable number.

18965971961 is a deficient number, since it is larger than the sum of its proper divisors (1).

18965971961 is an equidigital number, since it uses as much as digits as its factorization.

18965971961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7348320, while the sum is 62.

The spelling of 18965971961 in words is "eighteen billion, nine hundred sixty-five million, nine hundred seventy-one thousand, nine hundred sixty-one".