645378915 has 32 divisors (see below), whose sum is σ = 1043876160. Its totient is φ = 340465664.

The previous prime is 645378913. The next prime is 645378931. The reversal of 645378915 is 519873546.

It is a cyclic number.

It is not a de Polignac number, because 645378915 - 2¹ = 645378913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645378913) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1045687 + ... + 1046303.

It is an arithmetic number, because the mean of its divisors is an integer number (32621130).

Almost surely, 2^645378915 is an apocalyptic number.

645378915 is a deficient number, since it is larger than the sum of its proper divisors (398497245).

645378915 is a wasteful number, since it uses less digits than its factorization.

645378915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1271.

The product of its digits is 907200, while the sum is 48.

The square root of 645378915 is about 25404.3089848947. The cubic root of 645378915 is about 864.1814190047.

The spelling of 645378915 in words is "six hundred forty-five million, three hundred seventy-eight thousand, nine hundred fifteen".