665638487220 has 96 divisors (see below), whose sum is σ = 2170232725248. Its totient is φ = 149275256832.

The previous prime is 665638487203. The next prime is 665638487221. The reversal of 665638487220 is 22784836566.

665638487220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665638487221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14929189 + ... + 14973708.

It is an arithmetic number, because the mean of its divisors is an integer number (22606590888).

Almost surely, 2^665638487220 is an apocalyptic number.

665638487220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665638487220 is an abundant number, since it is smaller than the sum of its proper divisors (1504594238028).

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

665638487220 is a wasteful number, since it uses less digits than its factorization.

665638487220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29902969 (or 29902967 counting only the distinct ones).

The product of its (nonzero) digits is 23224320, while the sum is 57.

The spelling of 665638487220 in words is "six hundred sixty-five billion, six hundred thirty-eight million, four hundred eighty-seven thousand, two hundred twenty".