139839521656321 has 4 divisors (see below), whose sum is σ = 139839628778500. Its totient is φ = 139839414534144.

The previous prime is 139839521656291. The next prime is 139839521656333. The reversal of 139839521656321 is 123656125938931.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 33789399508225 + 106050122148096 = 5812865^2 + 10298064^2 .

It is a cyclic number.

It is not a de Polignac number, because 139839521656321 - 2⁹ = 139839521655809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139839521656381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51578496 + ... + 54221953.

It is an arithmetic number, because the mean of its divisors is an integer number (34959907194625).

Almost surely, 2^{139839521656321} is an apocalyptic number.

It is an amenable number.

139839521656321 is a deficient number, since it is larger than the sum of its proper divisors (107122179).

139839521656321 is a wasteful number, since it uses less digits than its factorization.

139839521656321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107122178.

The product of its digits is 62985600, while the sum is 64.

The spelling of 139839521656321 in words is "one hundred thirty-nine trillion, eight hundred thirty-nine billion, five hundred twenty-one million, six hundred fifty-six thousand, three hundred twenty-one".