645131850 has 48 divisors (see below), whose sum is σ = 1745379360. Its totient is φ = 156395200.

The previous prime is 645131821. The next prime is 645131891. The reversal of 645131850 is 58131546.

It is a Harshad number since it is a multiple of its sum of digits (33).

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 23 ways as a sum of consecutive naturals, for example, 193845 + ... + 197144.

It is an arithmetic number, because the mean of its divisors is an integer number (36362070).

Almost surely, 2^645131850 is an apocalyptic number.

645131850 is an abundant number, since it is smaller than the sum of its proper divisors (1100247510).

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

645131850 is a wasteful number, since it uses less digits than its factorization.

645131850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391015 (or 391010 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 645131850 is about 25399.4458600970. The cubic root of 645131850 is about 864.0711291535.

The spelling of 645131850 in words is "six hundred forty-five million, one hundred thirty-one thousand, eight hundred fifty".