644342121243446 has 4 divisors (see below), whose sum is σ = 966513181865172. Its totient is φ = 322171060621722.

The previous prime is 644342121243413. The next prime is 644342121243467.

644342121243446 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 644342121243394 and 644342121243403.

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 as a sum of consecutive naturals, namely, 161085530310860 + ... + 161085530310863.

It is an arithmetic number, because the mean of its divisors is an integer number (241628295466293).

Almost surely, 2^{644342121243446} is an apocalyptic number.

644342121243446 is a deficient number, since it is larger than the sum of its proper divisors (322171060621726).

644342121243446 is a wasteful number, since it uses less digits than its factorization.

644342121243446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322171060621725.

The product of its digits is 10616832, while the sum is 50.

The spelling of 644342121243446 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-six".