20831866 has 48 divisors (see below), whose sum is σ = 37417248. Its totient is φ = 8618400.

The previous prime is 20831861. The next prime is 20831869. The reversal of 20831866 is 66813802.

It is not an unprimeable number, because it can be changed into a prime (20831861) 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 23 ways as a sum of consecutive naturals, for example, 341476 + ... + 341536.

It is an arithmetic number, because the mean of its divisors is an integer number (779526).

Almost surely, 2^20831866 is an apocalyptic number.

20831866 is a deficient number, since it is larger than the sum of its proper divisors (16585382).

20831866 is a wasteful number, since it uses less digits than its factorization.

20831866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 20831866 is about 4564.1939047328. The cubic root of 20831866 is about 275.1541438857.

The spelling of 20831866 in words is "twenty million, eight hundred thirty-one thousand, eight hundred sixty-six".