644242000442 has 4 divisors (see below), whose sum is σ = 966363000666. Its totient is φ = 322121000220.

The previous prime is 644242000349. The next prime is 644242000469. The reversal of 644242000442 is 244000242446.

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

It can be written as a sum of positive squares in only one way, i.e., 456112480321 + 188129520121 = 675361^2 + 433739^2 .

It is a junction number, because it is equal to n+sod(n) for n = 644242000399 and 644242000408.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161060500109 + ... + 161060500112.

Almost surely, 2^644242000442 is an apocalyptic number.

644242000442 is a deficient number, since it is larger than the sum of its proper divisors (322121000224).

644242000442 is a wasteful number, since it uses less digits than its factorization.

644242000442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322121000223.

The product of its (nonzero) digits is 49152, while the sum is 32.

Adding to 644242000442 its reverse (244000242446), we get a palindrome (888242242888).

The spelling of 644242000442 in words is "six hundred forty-four billion, two hundred forty-two million, four hundred forty-two", and thus it is an aban number.