665949636 has 243 divisors, whose sum is σ = 2054738413. Its totient is φ = 181674240.

The previous prime is 665949629. The next prime is 665949637. The reversal of 665949636 is 636949566.

It is a happy number.

The square root of 665949636 is 25806.

It is a perfect power (a square), and thus also a powerful number.

665949636 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 518472900 + 147476736 = 22770^2 + 12144^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665949637) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 28954321 + ... + 28954343.

Almost surely, 2^665949636 is an apocalyptic number.

665949636 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

665949636 is the 25806-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665949636

665949636 is an abundant number, since it is smaller than the sum of its proper divisors (1388788777).

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

665949636 is a wasteful number, since it uses less digits than its factorization.

665949636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 56 counting only the distinct ones).

The product of its digits is 6298560, while the sum is 54.

The cubic root of 665949636 is about 873.2671603935.

The spelling of 665949636 in words is "six hundred sixty-five million, nine hundred forty-nine thousand, six hundred thirty-six".