645985744 has 20 divisors (see below), whose sum is σ = 1262676996. Its totient is φ = 320133632.

The previous prime is 645985741. The next prime is 645985787. The reversal of 645985744 is 447589546.

It can be written as a sum of positive squares in 2 ways, for example, as 39841344 + 606144400 = 6312^2 + 24620^2 .

It is a junction number, because it is equal to n+sod(n) for n = 645985691 and 645985700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645985741) 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, 176839 + ... + 180454.

Almost surely, 2^645985744 is an apocalyptic number.

It is an amenable number.

645985744 is a deficient number, since it is larger than the sum of its proper divisors (616691252).

645985744 is a wasteful number, since it uses less digits than its factorization.

645985744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357414 (or 357408 counting only the distinct ones).

The product of its digits is 4838400, while the sum is 52.

The square root of 645985744 is about 25416.2496053214. The cubic root of 645985744 is about 864.4521881388.

The spelling of 645985744 in words is "six hundred forty-five million, nine hundred eighty-five thousand, seven hundred forty-four".