644273497 has 8 divisors (see below), whose sum is σ = 779625216. Its totient is φ = 519749952.

The previous prime is 644273477. The next prime is 644273507. The reversal of 644273497 is 794372446.

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 644273497 - 2¹¹ = 644271449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644273417) 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, 2706913 + ... + 2707150.

It is an arithmetic number, because the mean of its divisors is an integer number (97453152).

Almost surely, 2^644273497 is an apocalyptic number.

It is an amenable number.

644273497 is a deficient number, since it is larger than the sum of its proper divisors (135351719).

644273497 is a wasteful number, since it uses less digits than its factorization.

644273497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5414087.

The product of its digits is 1016064, while the sum is 46.

The square root of 644273497 is about 25382.5431546959. The cubic root of 644273497 is about 863.6877412588.

The spelling of 644273497 in words is "six hundred forty-four million, two hundred seventy-three thousand, four hundred ninety-seven".