20639120639 has 4 divisors (see below), whose sum is σ = 20673577200. Its totient is φ = 20604664080.

The previous prime is 20639120617. The next prime is 20639120651. The reversal of 20639120639 is 93602193602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93602193602 = 2 ⋅46801096801.

It is a cyclic number.

It is not a de Polignac number, because 20639120639 - 2¹⁶ = 20639055103 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20639120596 and 20639120605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639123639) 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, 17227382 + ... + 17228579.

It is an arithmetic number, because the mean of its divisors is an integer number (5168394300).

Almost surely, 2^20639120639 is an apocalyptic number.

20639120639 is a deficient number, since it is larger than the sum of its proper divisors (34456561).

20639120639 is an equidigital number, since it uses as much as digits as its factorization.

20639120639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34456560.

The product of its (nonzero) digits is 104976, while the sum is 41.

The spelling of 20639120639 in words is "twenty billion, six hundred thirty-nine million, one hundred twenty thousand, six hundred thirty-nine".