665800387 has 16 divisors (see below), whose sum is σ = 786304000. Its totient is φ = 563439240.

The previous prime is 665800379. The next prime is 665800397. The reversal of 665800387 is 783008566.

It is not a de Polignac number, because 665800387 - 2³ = 665800379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665800397) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14812 + ... + 39382.

It is an arithmetic number, because the mean of its divisors is an integer number (49144000).

Almost surely, 2^665800387 is an apocalyptic number.

665800387 is a deficient number, since it is larger than the sum of its proper divisors (120503613).

665800387 is an equidigital number, since it uses as much as digits as its factorization.

665800387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24671 (or 24657 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 43.

The square root of 665800387 is about 25803.1080879804. The cubic root of 665800387 is about 873.2019182285.

The spelling of 665800387 in words is "six hundred sixty-five million, eight hundred thousand, three hundred eighty-seven".