665656637 has 2 divisors, whose sum is σ = 665656638. Its totient is φ = 665656636.

The previous prime is 665656631. The next prime is 665656643. The reversal of 665656637 is 736656566.

It is a balanced prime because it is at equal distance from previous prime (665656631) and next prime (665656643).

It can be written as a sum of positive squares in only one way, i.e., 588111001 + 77545636 = 24251^2 + 8806^2 .

It is a cyclic number.

It is not a de Polignac number, because 665656637 - 2²⁴ = 648879421 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665656631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332828318 + 332828319.

It is an arithmetic number, because the mean of its divisors is an integer number (332828319).

Almost surely, 2^665656637 is an apocalyptic number.

It is an amenable number.

665656637 is a deficient number, since it is larger than the sum of its proper divisors (1).

665656637 is an equidigital number, since it uses as much as digits as its factorization.

665656637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4082400, while the sum is 50.

The square root of 665656637 is about 25800.3224204660. The cubic root of 665656637 is about 873.1390706578.

The spelling of 665656637 in words is "six hundred sixty-five million, six hundred fifty-six thousand, six hundred thirty-seven".