644342121243445 has 8 divisors (see below), whose sum is σ = 773211144351744. Its totient is φ = 515473297755024.

The previous prime is 644342121243413. The next prime is 644342121243467. The reversal of 644342121243445 is 544342121243446.

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 644342121243445 - 2⁵ = 644342121243413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42709389 + ... + 55792258.

It is an arithmetic number, because the mean of its divisors is an integer number (96651393043968).

Almost surely, 2^{644342121243445} is an apocalyptic number.

It is an amenable number.

644342121243445 is a deficient number, since it is larger than the sum of its proper divisors (128869023108299).

644342121243445 is a wasteful number, since it uses less digits than its factorization.

644342121243445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99809939.

The product of its digits is 8847360, while the sum is 49.

Subtracting from 644342121243445 its reverse (544342121243446), we obtain a palindrome (99999999999999).

The spelling of 644342121243445 in words is "six hundred forty-four trillion, three hundred forty-two billion, one hundred twenty-one million, two hundred forty-three thousand, four hundred forty-five".