639944181443 has 16 divisors (see below), whose sum is σ = 774473172480. Its totient is φ = 516199533696.

The previous prime is 639944181439. The next prime is 639944181469. The reversal of 639944181443 is 344181449936.

It is not a de Polignac number, because 639944181443 - 2² = 639944181439 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639944141443) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 778778 + ... + 1373456.

It is an arithmetic number, because the mean of its divisors is an integer number (48404573280).

Almost surely, 2^639944181443 is an apocalyptic number.

639944181443 is a deficient number, since it is larger than the sum of its proper divisors (134528991037).

639944181443 is a wasteful number, since it uses less digits than its factorization.

639944181443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603746.

The product of its digits is 8957952, while the sum is 56.

The spelling of 639944181443 in words is "six hundred thirty-nine billion, nine hundred forty-four million, one hundred eighty-one thousand, four hundred forty-three".