665646564 has 96 divisors (see below), whose sum is σ = 1726792704. Its totient is φ = 197896320.

The previous prime is 665646529. The next prime is 665646593. The reversal of 665646564 is 465646566.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2351967 + ... + 2352249.

It is an arithmetic number, because the mean of its divisors is an integer number (17987424).

Almost surely, 2^665646564 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665646564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (863396352).

665646564 is an abundant number, since it is smaller than the sum of its proper divisors (1061146140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665646564 is a wasteful number, since it uses less digits than its factorization.

665646564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 577 (or 575 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 48.

The square root of 665646564 is about 25800.1272089887. The cubic root of 665646564 is about 873.1346663981.

The spelling of 665646564 in words is "six hundred sixty-five million, six hundred forty-six thousand, five hundred sixty-four".