665185920 has 256 divisors, whose sum is σ = 2481684480. Its totient is φ = 148377600.

The previous prime is 665185919. The next prime is 665185931. The reversal of 665185920 is 29581566.

665185920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 577345 + ... + 578495.

It is an arithmetic number, because the mean of its divisors is an integer number (9694080).

Almost surely, 2^665185920 is an apocalyptic number.

665185920 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 665185920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1240842240).

665185920 is an abundant number, since it is smaller than the sum of its proper divisors (1816498560).

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

665185920 is a wasteful number, since it uses less digits than its factorization.

665185920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1223 (or 1211 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 42.

The square root of 665185920 is about 25791.1984987127. The cubic root of 665185920 is about 872.9332096085.

The spelling of 665185920 in words is "six hundred sixty-five million, one hundred eighty-five thousand, nine hundred twenty".