8121289639 has 4 divisors (see below), whose sum is σ = 8232540256. Its totient is φ = 8010039024.

The previous prime is 8121289637. The next prime is 8121289667. The reversal of 8121289639 is 9369821218.

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

It is a cyclic number.

It is not a de Polignac number, because 8121289639 - 2¹ = 8121289637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8121289592 and 8121289601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8121289633) 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, 55625199 + ... + 55625344.

It is an arithmetic number, because the mean of its divisors is an integer number (2058135064).

Almost surely, 2^8121289639 is an apocalyptic number.

8121289639 is a deficient number, since it is larger than the sum of its proper divisors (111250617).

8121289639 is a wasteful number, since it uses less digits than its factorization.

8121289639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111250616.

The product of its digits is 373248, while the sum is 49.

The square root of 8121289639 is about 90118.1981566431. The cubic root of 8121289639 is about 2010.0568153870.

The spelling of 8121289639 in words is "eight billion, one hundred twenty-one million, two hundred eighty-nine thousand, six hundred thirty-nine".