665903657 has 2 divisors, whose sum is σ = 665903658. Its totient is φ = 665903656.

The previous prime is 665903629. The next prime is 665903663. The reversal of 665903657 is 756309566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 657973801 + 7929856 = 25651^2 + 2816^2 .

It is a cyclic number.

It is not a de Polignac number, because 665903657 - 2⁶ = 665903593 is a prime.

It is not a weakly prime, because it can be changed into another prime (665903057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332951828 + 332951829.

It is an arithmetic number, because the mean of its divisors is an integer number (332951829).

Almost surely, 2^665903657 is an apocalyptic number.

It is an amenable number.

665903657 is a deficient number, since it is larger than the sum of its proper divisors (1).

665903657 is an equidigital number, since it uses as much as digits as its factorization.

665903657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1020600, while the sum is 47.

The square root of 665903657 is about 25805.1091259076. The cubic root of 665903657 is about 873.2470623397.

The spelling of 665903657 in words is "six hundred sixty-five million, nine hundred three thousand, six hundred fifty-seven".