644347846 has 4 divisors (see below), whose sum is σ = 966521772. Its totient is φ = 322173922.

The previous prime is 644347811. The next prime is 644347849. The reversal of 644347846 is 648743446.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 644347796 and 644347805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644347849) by changing a digit.

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 as a sum of consecutive naturals, namely, 161086960 + ... + 161086963.

It is an arithmetic number, because the mean of its divisors is an integer number (241630443).

Almost surely, 2^644347846 is an apocalyptic number.

644347846 is a deficient number, since it is larger than the sum of its proper divisors (322173926).

644347846 is a wasteful number, since it uses less digits than its factorization.

644347846 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322173925.

The product of its digits is 1548288, while the sum is 46.

The square root of 644347846 is about 25384.0076820032. The cubic root of 644347846 is about 863.7209630971.

It can be divided in two parts, 6443 and 47846, that added together give a square (54289 = 233²).

The spelling of 644347846 in words is "six hundred forty-four million, three hundred forty-seven thousand, eight hundred forty-six".