660442640 has 80 divisors (see below), whose sum is σ = 1804009536. Its totient is φ = 221683200.

The previous prime is 660442621. The next prime is 660442687. The reversal of 660442640 is 46244066.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 660442597 and 660442606.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17426 + ... + 40305.

Almost surely, 2^660442640 is an apocalyptic number.

It is an amenable number.

660442640 is an abundant number, since it is smaller than the sum of its proper divisors (1143566896).

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

660442640 is a wasteful number, since it uses less digits than its factorization.

660442640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57768 (or 57762 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 660442640 is about 25699.0785827041. The cubic root of 660442640 is about 870.8533662254.

The spelling of 660442640 in words is "six hundred sixty million, four hundred forty-two thousand, six hundred forty".