645715191 has 32 divisors (see below), whose sum is σ = 968889600. Its totient is φ = 379116800.

The previous prime is 645715181. The next prime is 645715201. The reversal of 645715191 is 191517546.

It is an interprime number because it is at equal distance from previous prime (645715181) and next prime (645715201).

It is a cyclic number.

It is not a de Polignac number, because 645715191 - 2⁵ = 645715159 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645715121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 199996 + ... + 203198.

It is an arithmetic number, because the mean of its divisors is an integer number (30277800).

Almost surely, 2^645715191 is an apocalyptic number.

645715191 is a deficient number, since it is larger than the sum of its proper divisors (323174409).

645715191 is a wasteful number, since it uses less digits than its factorization.

645715191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3407.

The product of its digits is 37800, while the sum is 39.

The square root of 645715191 is about 25410.9266064817. The cubic root of 645715191 is about 864.3314874402.

The spelling of 645715191 in words is "six hundred forty-five million, seven hundred fifteen thousand, one hundred ninety-one".