645969380 has 24 divisors (see below), whose sum is σ = 1550326848. Its totient is φ = 221475168.

The previous prime is 645969361. The next prime is 645969407. The reversal of 645969380 is 83969546.

645969380 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2306894 + ... + 2307173.

It is an arithmetic number, because the mean of its divisors is an integer number (64596952).

Almost surely, 2^645969380 is an apocalyptic number.

It is an amenable number.

645969380 is an abundant number, since it is smaller than the sum of its proper divisors (904357468).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645969380 is a wasteful number, since it uses less digits than its factorization.

645969380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4614083 (or 4614081 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 50.

The square root of 645969380 is about 25415.9276832462. The cubic root of 645969380 is about 864.4448886924. Note that the first 3 decimals are identical.

The spelling of 645969380 in words is "six hundred forty-five million, nine hundred sixty-nine thousand, three hundred eighty".