665921136 has 20 divisors (see below), whose sum is σ = 1720296392. Its totient is φ = 221973696.

The previous prime is 665921131. The next prime is 665921147. The reversal of 665921136 is 631129566.

It is a junction number, because it is equal to n+sod(n) for n = 665921094 and 665921103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665921131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6936631 + ... + 6936726.

Almost surely, 2^665921136 is an apocalyptic number.

It is an amenable number.

665921136 is an abundant number, since it is smaller than the sum of its proper divisors (1054375256).

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

665921136 is a wasteful number, since it uses less digits than its factorization.

665921136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13873368 (or 13873362 counting only the distinct ones).

The product of its digits is 58320, while the sum is 39.

The square root of 665921136 is about 25805.4477969285. The cubic root of 665921136 is about 873.2547027602.

The spelling of 665921136 in words is "six hundred sixty-five million, nine hundred twenty-one thousand, one hundred thirty-six".