645641275 has 12 divisors (see below), whose sum is σ = 802900000. Its totient is φ = 515026080.

The previous prime is 645641237. The next prime is 645641291. The reversal of 645641275 is 572146546.

It is a happy number.

It is not a de Polignac number, because 645641275 - 2⁹ = 645640763 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28275 + ... + 45724.

Almost surely, 2^645641275 is an apocalyptic number.

645641275 is a deficient number, since it is larger than the sum of its proper divisors (157258725).

645641275 is a wasteful number, since it uses less digits than its factorization.

645641275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74358 (or 74353 counting only the distinct ones).

The product of its digits is 201600, while the sum is 40.

The square root of 645641275 is about 25409.4721511487. The cubic root of 645641275 is about 864.2985057350.

The spelling of 645641275 in words is "six hundred forty-five million, six hundred forty-one thousand, two hundred seventy-five".