665797920 has 96 divisors (see below), whose sum is σ = 2131738560. Its totient is φ = 174627840.

The previous prime is 665797919. The next prime is 665797931. The reversal of 665797920 is 29797566.

It is a tau number, because it is divible by the number of its divisors (96).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17911 + ... + 40649.

It is an arithmetic number, because the mean of its divisors is an integer number (22205610).

Almost surely, 2^665797920 is an apocalyptic number.

665797920 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 665797920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1065869280).

665797920 is an abundant number, since it is smaller than the sum of its proper divisors (1465940640).

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

665797920 is a wasteful number, since it uses less digits than its factorization.

665797920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22818 (or 22810 counting only the distinct ones).

The product of its (nonzero) digits is 1428840, while the sum is 51.

The square root of 665797920 is about 25803.0602836175. The cubic root of 665797920 is about 873.2008397311.

The spelling of 665797920 in words is "six hundred sixty-five million, seven hundred ninety-seven thousand, nine hundred twenty".