20782281 has 16 divisors (see below), whose sum is σ = 30047360. Its totient is φ = 12700800.

The previous prime is 20782277. The next prime is 20782291. The reversal of 20782281 is 18228702.

It is a happy number.

It is not a de Polignac number, because 20782281 - 2² = 20782277 is a prime.

It is a super-2 number, since 2×20782281² = 863806407125922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20782231) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 4125 + ... + 7653.

It is an arithmetic number, because the mean of its divisors is an integer number (1877960).

Almost surely, 2^20782281 is an apocalyptic number.

It is an amenable number.

20782281 is a deficient number, since it is larger than the sum of its proper divisors (9265079).

20782281 is a wasteful number, since it uses less digits than its factorization.

20782281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3696.

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 20782281 is about 4558.7587126322. The cubic root of 20782281 is about 274.9356587766.

The spelling of 20782281 in words is "twenty million, seven hundred eighty-two thousand, two hundred eighty-one".