644089947 has 8 divisors (see below), whose sum is σ = 858904080. Its totient is φ = 429334560.

The previous prime is 644089933. The next prime is 644089981. The reversal of 644089947 is 749980446.

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

It is not a de Polignac number, because 644089947 - 2¹⁸ = 643827803 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644089947.

It is not an unprimeable number, because it can be changed into a prime (644089847) 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, 33297 + ... + 48957.

It is an arithmetic number, because the mean of its divisors is an integer number (107363010).

Almost surely, 2^644089947 is an apocalyptic number.

644089947 is a deficient number, since it is larger than the sum of its proper divisors (214814133).

644089947 is a wasteful number, since it uses less digits than its factorization.

644089947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29373.

The product of its (nonzero) digits is 1741824, while the sum is 51.

The square root of 644089947 is about 25378.9272231905. The cubic root of 644089947 is about 863.6057134953.

The spelling of 644089947 in words is "six hundred forty-four million, eighty-nine thousand, nine hundred forty-seven".