664517997 has 48 divisors (see below), whose sum is σ = 1139506368. Its totient is φ = 367856640.

The previous prime is 664517983. The next prime is 664517999. The reversal of 664517997 is 799715466.

It is not a de Polignac number, because 664517997 - 2⁸ = 664517741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664517999) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 122178 + ... + 127500.

It is an arithmetic number, because the mean of its divisors is an integer number (23739716).

Almost surely, 2^664517997 is an apocalyptic number.

It is an amenable number.

664517997 is a deficient number, since it is larger than the sum of its proper divisors (474988371).

664517997 is a wasteful number, since it uses less digits than its factorization.

664517997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5450 (or 5447 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 54.

The square root of 664517997 is about 25778.2465850569. The cubic root of 664517997 is about 872.6409367215.

It can be divided in two parts, 6645 and 17997, that added together give a palindrome (24642).

The spelling of 664517997 in words is "six hundred sixty-four million, five hundred seventeen thousand, nine hundred ninety-seven".