645370218 has 24 divisors (see below), whose sum is σ = 1480555908. Its totient is φ = 202468992.

The previous prime is 645370213. The next prime is 645370237. The reversal of 645370218 is 812073546.

645370218 is a `hidden beast` number, since 645 + 3 + 7 + 0 + 2 + 1 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 547419609 + 97950609 = 23397^2 + 9897^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (645370211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1054221 + ... + 1054832.

Almost surely, 2^645370218 is an apocalyptic number.

645370218 is an abundant number, since it is smaller than the sum of its proper divisors (835185690).

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

645370218 is a wasteful number, since it uses less digits than its factorization.

645370218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109078 (or 2109075 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 645370218 is about 25404.1378125690. The cubic root of 645370218 is about 864.1775371406.

The spelling of 645370218 in words is "six hundred forty-five million, three hundred seventy thousand, two hundred eighteen".