665770400 has 72 divisors (see below), whose sum is σ = 1681415820. Its totient is φ = 257116160.

The previous prime is 665770363. The next prime is 665770447. The reversal of 665770400 is 4077566.

It can be written as a sum of positive squares in 6 ways, for example, as 105596176 + 560174224 = 10276^2 + 23668^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8852 + ... + 37548.

Almost surely, 2^665770400 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 665770400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (840707910).

665770400 is an abundant number, since it is smaller than the sum of its proper divisors (1015645420).

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

665770400 is a wasteful number, since it uses less digits than its factorization.

665770400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28746 (or 28733 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 35.

The square root of 665770400 is about 25802.5270080277. The cubic root of 665770400 is about 873.1888086441.

The spelling of 665770400 in words is "six hundred sixty-five million, seven hundred seventy thousand, four hundred".