20681992 has 16 divisors (see below), whose sum is σ = 38870460. Its totient is φ = 10316544.

The previous prime is 20681957. The next prime is 20681993. The reversal of 20681992 is 29918602.

It can be written as a sum of positive squares in 2 ways, for example, as 20666116 + 15876 = 4546^2 + 126^2 .

It is not an unprimeable number, because it can be changed into a prime (20681993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 828 + ... + 6484.

Almost surely, 2^20681992 is an apocalyptic number.

It is an amenable number.

20681992 is a deficient number, since it is larger than the sum of its proper divisors (18188468).

20681992 is a wasteful number, since it uses less digits than its factorization.

20681992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6120 (or 6116 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 20681992 is about 4547.7458152364. The cubic root of 20681992 is about 274.4926933710.

The spelling of 20681992 in words is "twenty million, six hundred eighty-one thousand, nine hundred ninety-two".