639552581691542 has 4 divisors (see below), whose sum is σ = 959328872537316. Its totient is φ = 319776290845770.

The previous prime is 639552581691493. The next prime is 639552581691587. The reversal of 639552581691542 is 245196185255936.

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

It is a congruent number.

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, 159888145422884 + ... + 159888145422887.

It is an arithmetic number, because the mean of its divisors is an integer number (239832218134329).

Almost surely, 2^{639552581691542} is an apocalyptic number.

639552581691542 is a deficient number, since it is larger than the sum of its proper divisors (319776290845774).

639552581691542 is a wasteful number, since it uses less digits than its factorization.

639552581691542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319776290845773.

The product of its digits is 699840000, while the sum is 71.

The spelling of 639552581691542 in words is "six hundred thirty-nine trillion, five hundred fifty-two billion, five hundred eighty-one million, six hundred ninety-one thousand, five hundred forty-two".