644867241 has 8 divisors (see below), whose sum is σ = 868171200. Its totient is φ = 425737392.

The previous prime is 644867221. The next prime is 644867243. The reversal of 644867241 is 142768446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644867241 - 2¹⁸ = 644605097 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644867193 and 644867202.

It is not an unprimeable number, because it can be changed into a prime (644867243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1043166 + ... + 1043783.

It is an arithmetic number, because the mean of its divisors is an integer number (108521400).

Almost surely, 2^644867241 is an apocalyptic number.

It is an amenable number.

644867241 is a deficient number, since it is larger than the sum of its proper divisors (223303959).

644867241 is a wasteful number, since it uses less digits than its factorization.

644867241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2087055.

The product of its digits is 258048, while the sum is 42.

The square root of 644867241 is about 25394.2363736341. The cubic root of 644867241 is about 863.9529764253.

The spelling of 644867241 in words is "six hundred forty-four million, eight hundred sixty-seven thousand, two hundred forty-one".