20831868 has 36 divisors (see below), whose sum is σ = 55757520. Its totient is φ = 6535296.

The previous prime is 20831861. The next prime is 20831869. The reversal of 20831868 is 86813802.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 16408 + ... + 17631.

It is an arithmetic number, because the mean of its divisors is an integer number (1548820).

Almost surely, 2^20831868 is an apocalyptic number.

It is an amenable number.

20831868 is an abundant number, since it is smaller than the sum of its proper divisors (34925652).

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

20831868 is a wasteful number, since it uses less digits than its factorization.

20831868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34066 (or 34061 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 20831868 is about 4564.1941238295. The cubic root of 20831868 is about 275.1541526912.

The spelling of 20831868 in words is "twenty million, eight hundred thirty-one thousand, eight hundred sixty-eight".