644224667 has 8 divisors (see below), whose sum is σ = 661469424. Its totient is φ = 627082848.

The previous prime is 644224663. The next prime is 644224703. The reversal of 644224667 is 766422446.

644224667 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 644224667 - 2² = 644224663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644224663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12968 + ... + 38165.

It is an arithmetic number, because the mean of its divisors is an integer number (82683678).

Almost surely, 2^644224667 is an apocalyptic number.

644224667 is a deficient number, since it is larger than the sum of its proper divisors (17244757).

644224667 is a wasteful number, since it uses less digits than its factorization.

644224667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51469.

The product of its digits is 387072, while the sum is 41.

The square root of 644224667 is about 25381.5812549179. The cubic root of 644224667 is about 863.6659208476.

The spelling of 644224667 in words is "six hundred forty-four million, two hundred twenty-four thousand, six hundred sixty-seven".