645739252 has 12 divisors (see below), whose sum is σ = 1133679456. Its totient is φ = 321830840.

The previous prime is 645739231. The next prime is 645739261. The reversal of 645739252 is 252937546.

It is a junction number, because it is equal to n+sod(n) for n = 645739199 and 645739208.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 258298 + ... + 260785.

It is an arithmetic number, because the mean of its divisors is an integer number (94473288).

Almost surely, 2^645739252 is an apocalyptic number.

It is an amenable number.

645739252 is a deficient number, since it is larger than the sum of its proper divisors (487940204).

645739252 is a wasteful number, since it uses less digits than its factorization.

645739252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519398 (or 519396 counting only the distinct ones).

The product of its digits is 453600, while the sum is 43.

The square root of 645739252 is about 25411.4000401395. The cubic root of 645739252 is about 864.3422230410.

The spelling of 645739252 in words is "six hundred forty-five million, seven hundred thirty-nine thousand, two hundred fifty-two".