644544445446 has 32 divisors (see below), whose sum is σ = 1562531990400. Its totient is φ = 195316498440.

The previous prime is 644544445427. The next prime is 644544445463.

644544445446 is a `hidden beast` number, since 6 + 4 + 4 + 54 + 4 + 44 + 544 + 6 = 666.

644544445446 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 = 644544445392 and 644544445401.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 542545236 + ... + 542546423.

It is an arithmetic number, because the mean of its divisors is an integer number (48829124700).

Almost surely, 2^644544445446 is an apocalyptic number.

644544445446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644544445446 is an abundant number, since it is smaller than the sum of its proper divisors (917987544954).

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

644544445446 is a wasteful number, since it uses less digits than its factorization.

644544445446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1085091681 (or 1085091675 counting only the distinct ones).

The product of its digits is 58982400, while the sum is 54.

The spelling of 644544445446 in words is "six hundred forty-four billion, five hundred forty-four million, four hundred forty-five thousand, four hundred forty-six".