645381376 has 18 divisors (see below), whose sum is σ = 1288242242. Its totient is φ = 322690560.

The previous prime is 645381337. The next prime is 645381397. The reversal of 645381376 is 673183546.

645381376 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 643941376 + 1440000 = 25376^2 + 1200^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1260255 + ... + 1260766.

Almost surely, 2^645381376 is an apocalyptic number.

It is an amenable number.

645381376 is a deficient number, since it is larger than the sum of its proper divisors (642860866).

645381376 is an equidigital number, since it uses as much as digits as its factorization.

645381376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2521037 (or 2521023 counting only the distinct ones).

The product of its digits is 362880, while the sum is 43.

The square root of 645381376 is about 25404.3574215133. The cubic root of 645381376 is about 864.1825174538.

The spelling of 645381376 in words is "six hundred forty-five million, three hundred eighty-one thousand, three hundred seventy-six".