644242404242446 has 4 divisors (see below), whose sum is σ = 966363606363672. Its totient is φ = 322121202121222.

The previous prime is 644242404242443. The next prime is 644242404242461.

644242404242446 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 = 644242404242393 and 644242404242402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644242404242443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161060601060610 + ... + 161060601060613.

It is an arithmetic number, because the mean of its divisors is an integer number (241590901590918).

Almost surely, 2^{644242404242446} is an apocalyptic number.

644242404242446 is a deficient number, since it is larger than the sum of its proper divisors (322121202121226).

644242404242446 is a wasteful number, since it uses less digits than its factorization.

644242404242446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322121202121225.

The product of its (nonzero) digits is 37748736, while the sum is 52.

It can be divided in two parts, 64424240 and 4242446, that added together give a palindrome (68666686).

The spelling of 644242404242446 in words is "six hundred forty-four trillion, two hundred forty-two billion, four hundred four million, two hundred forty-two thousand, four hundred forty-six".