665645560 has 32 divisors (see below), whose sum is σ = 1511452800. Its totient is φ = 263813760.

The previous prime is 665645551. The next prime is 665645569. The reversal of 665645560 is 65546566.

It is an interprime number because it is at equal distance from previous prime (665645551) and next prime (665645569).

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665645569) 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, 71976 + ... + 80695.

It is an arithmetic number, because the mean of its divisors is an integer number (47232900).

Almost surely, 2^665645560 is an apocalyptic number.

It is an amenable number.

665645560 is an abundant number, since it is smaller than the sum of its proper divisors (845807240).

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

665645560 is a wasteful number, since it uses less digits than its factorization.

665645560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152791 (or 152787 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 43.

The square root of 665645560 is about 25800.1077517130. The cubic root of 665645560 is about 873.1342274125.

The spelling of 665645560 in words is "six hundred sixty-five million, six hundred forty-five thousand, five hundred sixty".