644337733446 has 128 divisors (see below), whose sum is σ = 1581024614400. Its totient is φ = 192883680000.

The previous prime is 644337733441. The next prime is 644337733483.

644337733446 is a `hidden beast` number, since 64 + 43 + 3 + 77 + 33 + 446 = 666.

644337733446 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×644337733446² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 644337733392 and 644337733401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644337733441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 65073096 + ... + 65082996.

It is an arithmetic number, because the mean of its divisors is an integer number (12351754800).

Almost surely, 2^644337733446 is an apocalyptic number.

644337733446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 644337733446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (790512307200).

644337733446 is an abundant number, since it is smaller than the sum of its proper divisors (936686880954).

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

644337733446 is a wasteful number, since it uses less digits than its factorization.

644337733446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11243 (or 11237 counting only the distinct ones).

The product of its digits is 36578304, while the sum is 54.

The spelling of 644337733446 in words is "six hundred forty-four billion, three hundred thirty-seven million, seven hundred thirty-three thousand, four hundred forty-six".