20681900 has 18 divisors (see below), whose sum is σ = 44879940. Its totient is φ = 8272720.

The previous prime is 20681893. The next prime is 20681933. The reversal of 20681900 is 918602.

It is a super-2 number, since 2×20681900² = 855481975220000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20681900.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 103310 + ... + 103509.

It is an arithmetic number, because the mean of its divisors is an integer number (2493330).

Almost surely, 2^20681900 is an apocalyptic number.

20681900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20681900 is an abundant number, since it is smaller than the sum of its proper divisors (24198040).

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

20681900 is a wasteful number, since it uses less digits than its factorization.

20681900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206833 (or 206826 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 20681900 is about 4547.7357003238. The cubic root of 20681900 is about 274.4922863605.

The spelling of 20681900 in words is "twenty million, six hundred eighty-one thousand, nine hundred".