645259 has 4 divisors (see below), whose sum is σ = 679240. Its totient is φ = 611280.

The previous prime is 645257. The next prime is 645313. The reversal of 645259 is 952546.

645259 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645259 - 2¹ = 645257 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 645259.

It is not an unprimeable number, because it can be changed into a prime (645257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16962 + ... + 16999.

It is an arithmetic number, because the mean of its divisors is an integer number (169810).

2⁶⁴⁵²⁵⁹ is an apocalyptic number.

645259 is a deficient number, since it is larger than the sum of its proper divisors (33981).

645259 is a wasteful number, since it uses less digits than its factorization.

645259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33980.

The product of its digits is 10800, while the sum is 31.

The square root of 645259 is about 803.2801503834. The cubic root of 645259 is about 86.4127892448.

The spelling of 645259 in words is "six hundred forty-five thousand, two hundred fifty-nine".