665387136 has 160 divisors (see below), whose sum is σ = 2049389100. Its totient is φ = 214050816.

The previous prime is 665387119. The next prime is 665387141. The reversal of 665387136 is 631783566.

It can be written as a sum of positive squares in 2 ways, for example, as 581774400 + 83612736 = 24120^2 + 9144^2 .

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

Its product of digits (544320) is a multiple of the sum of its prime factors (2268).

It is a junction number, because it is equal to n+sod(n) for n = 665387091 and 665387100.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 299566 + ... + 301778.

Almost surely, 2^665387136 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 665387136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1024694550).

665387136 is an abundant number, since it is smaller than the sum of its proper divisors (1384001964).

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

665387136 is a wasteful number, since it uses less digits than its factorization.

665387136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2268 (or 2247 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The square root of 665387136 is about 25795.0990693969. The cubic root of 665387136 is about 873.0212203011.

The spelling of 665387136 in words is "six hundred sixty-five million, three hundred eighty-seven thousand, one hundred thirty-six".