665161631 has 2 divisors, whose sum is σ = 665161632. Its totient is φ = 665161630.

The previous prime is 665161597. The next prime is 665161649. The reversal of 665161631 is 136161566.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665161631 is a prime.

It is a super-2 number, since 2×665161631² = 884879990709160322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 665161591 and 665161600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665161681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332580815 + 332580816.

It is an arithmetic number, because the mean of its divisors is an integer number (332580816).

Almost surely, 2^665161631 is an apocalyptic number.

665161631 is a deficient number, since it is larger than the sum of its proper divisors (1).

665161631 is an equidigital number, since it uses as much as digits as its factorization.

665161631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 35.

The square root of 665161631 is about 25790.7276167230. The cubic root of 665161631 is about 872.9225845425.

The spelling of 665161631 in words is "six hundred sixty-five million, one hundred sixty-one thousand, six hundred thirty-one".