665949900 has 288 divisors, whose sum is σ = 2431844352. Its totient is φ = 136684800.

The previous prime is 665949853. The next prime is 665949913. The reversal of 665949900 is 9949566.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 665949900.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2933587 + ... + 2933813.

It is an arithmetic number, because the mean of its divisors is an integer number (8443904).

Almost surely, 2^665949900 is an apocalyptic number.

665949900 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665949900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1215922176).

665949900 is an abundant number, since it is smaller than the sum of its proper divisors (1765894452).

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

665949900 is a wasteful number, since it uses less digits than its factorization.

665949900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389 (or 382 counting only the distinct ones).

The product of its (nonzero) digits is 524880, while the sum is 48.

The square root of 665949900 is about 25806.0051150890. The cubic root of 665949900 is about 873.2672757889.

The spelling of 665949900 in words is "six hundred sixty-five million, nine hundred forty-nine thousand, nine hundred".