20439840859 has 4 divisors (see below), whose sum is σ = 21328529616. Its totient is φ = 19551152104.

The previous prime is 20439840853. The next prime is 20439840907. The reversal of 20439840859 is 95804893402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95804893402 = 2 ⋅47902446701.

It is a cyclic number.

It is not a de Polignac number, because 20439840859 - 2⁹ = 20439840347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20439840853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 444344344 + ... + 444344389.

It is an arithmetic number, because the mean of its divisors is an integer number (5332132404).

Almost surely, 2^20439840859 is an apocalyptic number.

20439840859 is a deficient number, since it is larger than the sum of its proper divisors (888688757).

20439840859 is an equidigital number, since it uses as much as digits as its factorization.

20439840859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 888688756.

The product of its (nonzero) digits is 2488320, while the sum is 52.

The spelling of 20439840859 in words is "twenty billion, four hundred thirty-nine million, eight hundred forty thousand, eight hundred fifty-nine".