645238 has 16 divisors (see below), whose sum is σ = 1068480. Its totient is φ = 289800.

The previous prime is 645233. The next prime is 645257. The reversal of 645238 is 832546.

645238 = T₃₃₇ + T₃₃₈ + ... + T₃₄₇.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2953 + ... + 3163.

It is an arithmetic number, because the mean of its divisors is an integer number (66780).

645238 is a Friedman number, since it can be written as 83*(6^5-2)-4, using all its digits and the basic arithmetic operations.

2⁶⁴⁵²³⁸ is an apocalyptic number.

645238 is a deficient number, since it is larger than the sum of its proper divisors (423242).

645238 is a wasteful number, since it uses less digits than its factorization.

645238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363.

The product of its digits is 5760, while the sum is 28.

The square root of 645238 is about 803.2670788723. The cubic root of 645238 is about 86.4118517978.

The spelling of 645238 in words is "six hundred forty-five thousand, two hundred thirty-eight".