20983281 has 16 divisors (see below), whose sum is σ = 30663360. Its totient is φ = 12657920.

The previous prime is 20983273. The next prime is 20983289. The reversal of 20983281 is 18238902.

It is an interprime number because it is at equal distance from previous prime (20983273) and next prime (20983289).

It is not a de Polignac number, because 20983281 - 2³ = 20983273 is a prime.

It is a super-2 number, since 2×20983281² = 880596163049922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20983289) 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 15 ways as a sum of consecutive naturals, for example, 6325 + ... + 9053.

It is an arithmetic number, because the mean of its divisors is an integer number (1916460).

Almost surely, 2^20983281 is an apocalyptic number.

It is an amenable number.

20983281 is a deficient number, since it is larger than the sum of its proper divisors (9680079).

20983281 is a wasteful number, since it uses less digits than its factorization.

20983281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2976.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 20983281 is about 4580.7511392784. The cubic root of 20983281 is about 275.8191816067.

The spelling of 20983281 in words is "twenty million, nine hundred eighty-three thousand, two hundred eighty-one".