645099 has 32 divisors (see below), whose sum is σ = 1128960. Its totient is φ = 317952.

The previous prime is 645097. The next prime is 645131. The reversal of 645099 is 990546.

It is a happy number.

It is not a de Polignac number, because 645099 - 2¹ = 645097 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645099.

It is not an unprimeable number, because it can be changed into a prime (645091) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4572 + ... + 4710.

It is an arithmetic number, because the mean of its divisors is an integer number (35280).

2⁶⁴⁵⁰⁹⁹ is an apocalyptic number.

645099 is a deficient number, since it is larger than the sum of its proper divisors (483861).

645099 is a wasteful number, since it uses less digits than its factorization.

645099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179.

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 645099 is about 803.1805525534. The cubic root of 645099 is about 86.4056462788.

The spelling of 645099 in words is "six hundred forty-five thousand, ninety-nine".