644011024 has 10 divisors (see below), whose sum is σ = 1247771390. Its totient is φ = 322005504.

The previous prime is 644010989. The next prime is 644011087. The reversal of 644011024 is 420110446.

It can be written as a sum of positive squares in only one way, i.e., 359481600 + 284529424 = 18960^2 + 16868^2 .

It is a junction number, because it is equal to n+sod(n) for n = 644010986 and 644011004.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20125329 + ... + 20125360.

It is an arithmetic number, because the mean of its divisors is an integer number (124777139).

Almost surely, 2^644011024 is an apocalyptic number.

It is an amenable number.

644011024 is a deficient number, since it is larger than the sum of its proper divisors (603760366).

644011024 is a wasteful number, since it uses less digits than its factorization.

644011024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40250697 (or 40250691 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 644011024 is about 25377.3722831975. The cubic root of 644011024 is about 863.5704383301.

The spelling of 644011024 in words is "six hundred forty-four million, eleven thousand, twenty-four".