645731187 has 8 divisors (see below), whose sum is σ = 898408704. Its totient is φ = 411770568.

The previous prime is 645731173. The next prime is 645731189. The reversal of 645731187 is 781137546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645731187 - 2⁶ = 645731123 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (645731189) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4679143 + ... + 4679280.

It is an arithmetic number, because the mean of its divisors is an integer number (112301088).

Almost surely, 2^645731187 is an apocalyptic number.

645731187 is a deficient number, since it is larger than the sum of its proper divisors (252677517).

645731187 is a wasteful number, since it uses less digits than its factorization.

645731187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9358449.

The product of its digits is 141120, while the sum is 42.

The square root of 645731187 is about 25411.2413510242. The cubic root of 645731187 is about 864.3386246076.

The spelling of 645731187 in words is "six hundred forty-five million, seven hundred thirty-one thousand, one hundred eighty-seven".