665656577 has 2 divisors, whose sum is σ = 665656578. Its totient is φ = 665656576.

The previous prime is 665656567. The next prime is 665656601. The reversal of 665656577 is 775656566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 394856641 + 270799936 = 19871^2 + 16456^2 .

It is a cyclic number.

It is not a de Polignac number, because 665656577 - 2¹⁶ = 665591041 is a prime.

It is not a weakly prime, because it can be changed into another prime (665656567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332828288 + 332828289.

It is an arithmetic number, because the mean of its divisors is an integer number (332828289).

Almost surely, 2^665656577 is an apocalyptic number.

It is an amenable number.

665656577 is a deficient number, since it is larger than the sum of its proper divisors (1).

665656577 is an equidigital number, since it uses as much as digits as its factorization.

665656577 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7938000, while the sum is 53.

The square root of 665656577 is about 25800.3212576898. The cubic root of 665656577 is about 873.1390444239.

The spelling of 665656577 in words is "six hundred sixty-five million, six hundred fifty-six thousand, five hundred seventy-seven".