20831806 has 4 divisors (see below), whose sum is σ = 31247712. Its totient is φ = 10415902.

The previous prime is 20831803. The next prime is 20831807. The reversal of 20831806 is 60813802.

20831806 is nontrivially palindromic in base 14.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20831803) 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 as a sum of consecutive naturals, namely, 5207950 + ... + 5207953.

It is an arithmetic number, because the mean of its divisors is an integer number (7811928).

Almost surely, 2^20831806 is an apocalyptic number.

20831806 is a deficient number, since it is larger than the sum of its proper divisors (10415906).

20831806 is a wasteful number, since it uses less digits than its factorization.

20831806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10415905.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 20831806 is about 4564.1873318259. The cubic root of 20831806 is about 275.1538797188.

The spelling of 20831806 in words is "twenty million, eight hundred thirty-one thousand, eight hundred six".