645744464 has 10 divisors (see below), whose sum is σ = 1251129930. Its totient is φ = 322872224.

The previous prime is 645744443. The next prime is 645744487. The reversal of 645744464 is 464447546.

It is a happy number.

645744464 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., 489294400 + 156450064 = 22120^2 + 12508^2 .

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, 20179499 + ... + 20179530.

It is an arithmetic number, because the mean of its divisors is an integer number (125112993).

Almost surely, 2^645744464 is an apocalyptic number.

It is an amenable number.

645744464 is a deficient number, since it is larger than the sum of its proper divisors (605385466).

645744464 is a wasteful number, since it uses less digits than its factorization.

645744464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40359037 (or 40359031 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 44.

The square root of 645744464 is about 25411.5025923301. The cubic root of 645744464 is about 864.3445485099.

The spelling of 645744464 in words is "six hundred forty-five million, seven hundred forty-four thousand, four hundred sixty-four".