645995899 has 8 divisors (see below), whose sum is σ = 655723728. Its totient is φ = 636333600.

The previous prime is 645995879. The next prime is 645995941. The reversal of 645995899 is 998599546.

It is a happy number.

645995899 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645995899 - 2²³ = 637607291 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645995899.

It is not an unprimeable number, because it can be changed into a prime (645995809) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3664 + ... + 36130.

It is an arithmetic number, because the mean of its divisors is an integer number (81965466).

Almost surely, 2^645995899 is an apocalyptic number.

645995899 is a deficient number, since it is larger than the sum of its proper divisors (9727829).

645995899 is a wasteful number, since it uses less digits than its factorization.

645995899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32765.

The product of its digits is 31492800, while the sum is 64.

The square root of 645995899 is about 25416.4493783062. The cubic root of 645995899 is about 864.4567178910.

The spelling of 645995899 in words is "six hundred forty-five million, nine hundred ninety-five thousand, eight hundred ninety-nine".