665864153800 has 192 divisors, whose sum is σ = 1610231380560. Its totient is φ = 255909888000.

The previous prime is 665864153777. The next prime is 665864153819. The reversal of 665864153800 is 8351468566.

It can be written as a sum of positive squares in 24 ways, for example, as 64423577124 + 601440576676 = 253818^2 + 775526^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 155828464 + ... + 155832736.

Almost surely, 2^665864153800 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 665864153800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (805115690280).

665864153800 is an abundant number, since it is smaller than the sum of its proper divisors (944367226760).

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

665864153800 is a wasteful number, since it uses less digits than its factorization.

665864153800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4644 (or 4635 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 52.

The spelling of 665864153800 in words is "six hundred sixty-five billion, eight hundred sixty-four million, one hundred fifty-three thousand, eight hundred".