640849275 has 54 divisors (see below), whose sum is σ = 1261720460. Its totient is φ = 310701600.

The previous prime is 640849247. The next prime is 640849291. The reversal of 640849275 is 572948046.

It is a happy number.

It is not a de Polignac number, because 640849275 - 2⁵ = 640849243 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 640849275.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 15456 + ... + 38994.

Almost surely, 2^640849275 is an apocalyptic number.

640849275 is a deficient number, since it is larger than the sum of its proper divisors (620871185).

640849275 is a wasteful number, since it uses less digits than its factorization.

640849275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23577 (or 23558 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The square root of 640849275 is about 25315.0009875568. Note that the first 3 decimals coincide. The cubic root of 640849275 is about 862.1548965923.

The spelling of 640849275 in words is "six hundred forty million, eight hundred forty-nine thousand, two hundred seventy-five".