644424253360 has 40 divisors (see below), whose sum is σ = 1503012903696. Its totient is φ = 256956537600.

The previous prime is 644424253351. The next prime is 644424253367. The reversal of 644424253360 is 63352424446.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (644424253367) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12680166 + ... + 12730885.

Almost surely, 2^644424253360 is an apocalyptic number.

It is an amenable number.

644424253360 is an abundant number, since it is smaller than the sum of its proper divisors (858588650336).

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

644424253360 is a wasteful number, since it uses less digits than its factorization.

644424253360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25411381 (or 25411375 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 43.

The spelling of 644424253360 in words is "six hundred forty-four billion, four hundred twenty-four million, two hundred fifty-three thousand, three hundred sixty".