644733337446 has 64 divisors (see below), whose sum is σ = 1654930517760. Its totient is φ = 183881162880.

The previous prime is 644733337441. The next prime is 644733337499.

644733337446 is a `hidden beast` number, since 64 + 473 + 3 + 3 + 3 + 74 + 46 = 666.

644733337446 is nontrivially palindromic in base 10.

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 = 644733337392 and 644733337401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644733337441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31913716 + ... + 31933911.

It is an arithmetic number, because the mean of its divisors is an integer number (25858289340).

Almost surely, 2^644733337446 is an apocalyptic number.

644733337446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644733337446 is an abundant number, since it is smaller than the sum of its proper divisors (1010197180314).

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

644733337446 is a wasteful number, since it uses less digits than its factorization.

644733337446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63847666 (or 63847660 counting only the distinct ones).

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

The spelling of 644733337446 in words is "six hundred forty-four billion, seven hundred thirty-three million, three hundred thirty-seven thousand, four hundred forty-six".