665026513 has 2 divisors, whose sum is σ = 665026514. Its totient is φ = 665026512.

The previous prime is 665026459. The next prime is 665026517. The reversal of 665026513 is 315620566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 469502224 + 195524289 = 21668^2 + 13983^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665026513 is a prime.

It is not a weakly prime, because it can be changed into another prime (665026517) 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, 332513256 + 332513257.

It is an arithmetic number, because the mean of its divisors is an integer number (332513257).

Almost surely, 2^665026513 is an apocalyptic number.

It is an amenable number.

665026513 is a deficient number, since it is larger than the sum of its proper divisors (1).

665026513 is an equidigital number, since it uses as much as digits as its factorization.

665026513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32400, while the sum is 34.

The square root of 665026513 is about 25788.1079763522. The cubic root of 665026513 is about 872.8634733252.

The spelling of 665026513 in words is "six hundred sixty-five million, twenty-six thousand, five hundred thirteen".