645757250 has 16 divisors (see below), whose sum is σ = 1208858040. Its totient is φ = 258302800.

The previous prime is 645757241. The next prime is 645757253. The reversal of 645757250 is 52757546.

It can be written as a sum of positive squares in 4 ways, for example, as 313679521 + 332077729 = 17711^2 + 18223^2 .

It is a junction number, because it is equal to n+sod(n) for n = 645757198 and 645757207.

It is not an unprimeable number, because it can be changed into a prime (645757253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1291265 + ... + 1291764.

Almost surely, 2^645757250 is an apocalyptic number.

645757250 is a deficient number, since it is larger than the sum of its proper divisors (563100790).

645757250 is a wasteful number, since it uses less digits than its factorization.

645757250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2583046 (or 2583036 counting only the distinct ones).

The product of its (nonzero) digits is 294000, while the sum is 41.

The square root of 645757250 is about 25411.7541700686. The cubic root of 645757250 is about 864.3502532621.

The spelling of 645757250 in words is "six hundred forty-five million, seven hundred fifty-seven thousand, two hundred fifty".