640329187 has 4 divisors (see below), whose sum is σ = 641080720. Its totient is φ = 639577656.

The previous prime is 640329167. The next prime is 640329229. The reversal of 640329187 is 781923046.

640329187 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 781923046 = 2 ⋅390961523.

It is a cyclic number.

It is not a de Polignac number, because 640329187 - 2⁷ = 640329059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640329167) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374487 + ... + 376192.

It is an arithmetic number, because the mean of its divisors is an integer number (160270180).

Almost surely, 2^640329187 is an apocalyptic number.

640329187 is a deficient number, since it is larger than the sum of its proper divisors (751533).

640329187 is an equidigital number, since it uses as much as digits as its factorization.

640329187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751532.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 640329187 is about 25304.7265742983. The cubic root of 640329187 is about 861.9216031652.

The spelling of 640329187 in words is "six hundred forty million, three hundred twenty-nine thousand, one hundred eighty-seven".