645399772 has 12 divisors (see below), whose sum is σ = 1130695776. Its totient is φ = 322343840.

The previous prime is 645399707. The next prime is 645399773. The reversal of 645399772 is 277993546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645399773) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 84913 + ... + 92200.

It is an arithmetic number, because the mean of its divisors is an integer number (94224648).

Almost surely, 2^645399772 is an apocalyptic number.

It is an amenable number.

645399772 is a deficient number, since it is larger than the sum of its proper divisors (485296004).

645399772 is a wasteful number, since it uses less digits than its factorization.

645399772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178028 (or 178026 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 52.

The square root of 645399772 is about 25404.7194828048. The cubic root of 645399772 is about 864.1907282839.

The spelling of 645399772 in words is "six hundred forty-five million, three hundred ninety-nine thousand, seven hundred seventy-two".