20439840858 has 16 divisors (see below), whose sum is σ = 40888656576. Its totient is φ = 6811784480.

The previous prime is 20439840853. The next prime is 20439840907. The reversal of 20439840858 is 85804893402.

It is a self number, because there is not a number n which added to its sum of digits gives 20439840858.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 344163 + ... + 399158.

It is an arithmetic number, because the mean of its divisors is an integer number (2555541036).

Almost surely, 2^20439840858 is an apocalyptic number.

20439840858 is an abundant number, since it is smaller than the sum of its proper divisors (20448815718).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20439840858 is a wasteful number, since it uses less digits than its factorization.

20439840858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747909.

The product of its (nonzero) digits is 2211840, while the sum is 51.

The spelling of 20439840858 in words is "twenty billion, four hundred thirty-nine million, eight hundred forty thousand, eight hundred fifty-eight".