665022640 has 40 divisors (see below), whose sum is σ = 1550146320. Its totient is φ = 265326336.

The previous prime is 665022619. The next prime is 665022647. The reversal of 665022640 is 46220566.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×665022640² = 884510223425139200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665022647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21291 + ... + 42229.

It is an arithmetic number, because the mean of its divisors is an integer number (38753658).

Almost surely, 2^665022640 is an apocalyptic number.

It is an amenable number.

665022640 is an abundant number, since it is smaller than the sum of its proper divisors (885123680).

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

665022640 is a wasteful number, since it uses less digits than its factorization.

665022640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21349 (or 21343 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 665022640 is about 25788.0328834907. The cubic root of 665022640 is about 872.8617788530.

The spelling of 665022640 in words is "six hundred sixty-five million, twenty-two thousand, six hundred forty".