664311561 has 16 divisors (see below), whose sum is σ = 912135168. Its totient is φ = 429795200.

The previous prime is 664311559. The next prime is 664311563. The reversal of 664311561 is 165113466.

It is an interprime number because it is at equal distance from previous prime (664311559) and next prime (664311563).

It is a cyclic number.

It is not a de Polignac number, because 664311561 - 2¹ = 664311559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664311563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9355 + ... + 37631.

It is an arithmetic number, because the mean of its divisors is an integer number (57008448).

Almost surely, 2^664311561 is an apocalyptic number.

It is an amenable number.

664311561 is a deficient number, since it is larger than the sum of its proper divisors (247823607).

664311561 is a wasteful number, since it uses less digits than its factorization.

664311561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28512.

The product of its digits is 12960, while the sum is 33.

The square root of 664311561 is about 25774.2422003053. The cubic root of 664311561 is about 872.5505638685.

The spelling of 664311561 in words is "six hundred sixty-four million, three hundred eleven thousand, five hundred sixty-one".