644544445392 has 100 divisors (see below), whose sum is σ = 1889112829120. Its totient is φ = 212128517952.

The previous prime is 644544445387. The next prime is 644544445421. The reversal of 644544445392 is 293544445446.

644544445392 is a `hidden beast` number, since 6 + 4 + 4 + 544 + 4 + 4 + 5 + 3 + 92 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3045298 + ... + 3250065.

Almost surely, 2^644544445392 is an apocalyptic number.

It is an amenable number.

644544445392 is an abundant number, since it is smaller than the sum of its proper divisors (1244568383728).

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

644544445392 is a wasteful number, since it uses less digits than its factorization.

644544445392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6295462 (or 6295447 counting only the distinct ones).

The product of its digits is 33177600, while the sum is 54.

Adding to 644544445392 its sum of digits (54), we get a palindrome (644544445446).

It can be divided in two parts, 644544 and 445392, that added together give a square (1089936 = 1044²).

The spelling of 644544445392 in words is "six hundred forty-four billion, five hundred forty-four million, four hundred forty-five thousand, three hundred ninety-two".