644412132 has 576 divisors, whose sum is σ = 2413152000. Its totient is φ = 146313216.

The previous prime is 644412079. The next prime is 644412133. The reversal of 644412132 is 231214446.

It is a happy number.

644412132 is a `hidden beast` number, since 6 + 4 + 441 + 213 + 2 = 666.

644412132 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 644412096 and 644412105.

It is not an unprimeable number, because it can be changed into a prime (644412133) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 22221094 + ... + 22221122.

It is an arithmetic number, because the mean of its divisors is an integer number (4189500).

Almost surely, 2^644412132 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644412132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1206576000).

644412132 is an abundant number, since it is smaller than the sum of its proper divisors (1768739868).

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

644412132 is a wasteful number, since it uses less digits than its factorization.

644412132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 90 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

The square root of 644412132 is about 25385.2739201294. The cubic root of 644412132 is about 863.7496863609.

Adding to 644412132 its reverse (231214446), we get a palindrome (875626578).

The spelling of 644412132 in words is "six hundred forty-four million, four hundred twelve thousand, one hundred thirty-two".