20406859 has 4 divisors (see below), whose sum is σ = 22262040. Its totient is φ = 18551680.

The previous prime is 20406833. The next prime is 20406917. The reversal of 20406859 is 95860402.

It is a happy number.

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 20406859 - 2¹⁵ = 20374091 is a prime.

It is a super-3 number, since 3×20406859³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20406829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 927574 + ... + 927595.

It is an arithmetic number, because the mean of its divisors is an integer number (5565510).

Almost surely, 2^20406859 is an apocalyptic number.

20406859 is a deficient number, since it is larger than the sum of its proper divisors (1855181).

20406859 is a wasteful number, since it uses less digits than its factorization.

20406859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1855180.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 20406859 is about 4517.3951565034. The cubic root of 20406859 is about 273.2700615330.

The spelling of 20406859 in words is "twenty million, four hundred six thousand, eight hundred fifty-nine".