644113420 has 24 divisors (see below), whose sum is σ = 1371692448. Its totient is φ = 254016000.

The previous prime is 644113417. The next prime is 644113451. The reversal of 644113420 is 24311446.

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 in 7 ways as a sum of consecutive naturals, for example, 225381 + ... + 228220.

It is an arithmetic number, because the mean of its divisors is an integer number (57153852).

Almost surely, 2^644113420 is an apocalyptic number.

It is an amenable number.

644113420 is an abundant number, since it is smaller than the sum of its proper divisors (727579028).

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

644113420 is a wasteful number, since it uses less digits than its factorization.

644113420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453681 (or 453679 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 644113420 is about 25379.3896695724. The cubic root of 644113420 is about 863.6162043544.

Adding to 644113420 its reverse (24311446), we get a palindrome (668424866).

The spelling of 644113420 in words is "six hundred forty-four million, one hundred thirteen thousand, four hundred twenty".