644426343 has 12 divisors (see below), whose sum is σ = 1015459848. Its totient is φ = 390561360.

The previous prime is 644426333. The next prime is 644426369. The reversal of 644426343 is 343624446.

644426343 is a `hidden beast` number, since 644 + 4 + 2 + 6 + 3 + 4 + 3 = 666.

644426343 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644426343 - 2¹⁶ = 644360807 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644426298 and 644426307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644426303) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3254580 + ... + 3254777.

It is an arithmetic number, because the mean of its divisors is an integer number (84621654).

Almost surely, 2^644426343 is an apocalyptic number.

644426343 is a deficient number, since it is larger than the sum of its proper divisors (371033505).

644426343 is a wasteful number, since it uses less digits than its factorization.

644426343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6509374 (or 6509371 counting only the distinct ones).

The product of its digits is 165888, while the sum is 36.

The square root of 644426343 is about 25385.5538249612. The cubic root of 644426343 is about 863.7560356395.

The spelling of 644426343 in words is "six hundred forty-four million, four hundred twenty-six thousand, three hundred forty-three".