644799417997 has 4 divisors (see below), whose sum is σ = 736913620576. Its totient is φ = 552685215420.

The previous prime is 644799417979. The next prime is 644799418007. The reversal of 644799417997 is 799714997446.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644799417997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644799412997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46057101279 + ... + 46057101292.

It is an arithmetic number, because the mean of its divisors is an integer number (184228405144).

Almost surely, 2^644799417997 is an apocalyptic number.

It is an amenable number.

644799417997 is a deficient number, since it is larger than the sum of its proper divisors (92114202579).

644799417997 is an equidigital number, since it uses as much as digits as its factorization.

644799417997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92114202578.

The product of its digits is 864162432, while the sum is 76.

The spelling of 644799417997 in words is "six hundred forty-four billion, seven hundred ninety-nine million, four hundred seventeen thousand, nine hundred ninety-seven".