645739250 has 32 divisors (see below), whose sum is σ = 1301816880. Its totient is φ = 238425600.

The previous prime is 645739231. The next prime is 645739261. The reversal of 645739250 is 52937546.

It can be written as a sum of positive squares in 8 ways, for example, as 19088161 + 626651089 = 4369^2 + 25033^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 645739198 and 645739207.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96095 + ... + 102594.

Almost surely, 2^645739250 is an apocalyptic number.

645739250 is an abundant number, since it is smaller than the sum of its proper divisors (656077630).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645739250 is a wasteful number, since it uses less digits than its factorization.

645739250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198719 (or 198709 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 41.

The square root of 645739250 is about 25411.4000007870. The cubic root of 645739250 is about 864.3422221487.

The spelling of 645739250 in words is "six hundred forty-five million, seven hundred thirty-nine thousand, two hundred fifty".