20840859 has 12 divisors (see below), whose sum is σ = 32419296. Its totient is φ = 12825072.

The previous prime is 20840839. The next prime is 20840873. The reversal of 20840859 is 95804802.

It is not a de Polignac number, because 20840859 - 2²⁴ = 4063643 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20840839) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 88947 + ... + 89180.

It is an arithmetic number, because the mean of its divisors is an integer number (2701608).

Almost surely, 2^20840859 is an apocalyptic number.

20840859 is a deficient number, since it is larger than the sum of its proper divisors (11578437).

20840859 is a wasteful number, since it uses less digits than its factorization.

20840859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178146 (or 178143 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20840859 is about 4565.1789669190. The cubic root of 20840859 is about 275.1937323577.

The spelling of 20840859 in words is "twenty million, eight hundred forty thousand, eight hundred fifty-nine".