20782081 has 2 divisors, whose sum is σ = 20782082. Its totient is φ = 20782080.

The previous prime is 20782061. The next prime is 20782093. The reversal of 20782081 is 18028702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12852225 + 7929856 = 3585^2 + 2816^2 .

It is a cyclic number.

It is not a de Polignac number, because 20782081 - 2¹¹ = 20780033 is a prime.

It is a super-2 number, since 2×20782081² = 863789781381122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20782031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10391040 + 10391041.

It is an arithmetic number, because the mean of its divisors is an integer number (10391041).

Almost surely, 2^20782081 is an apocalyptic number.

It is an amenable number.

20782081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20782081 is an equidigital number, since it uses as much as digits as its factorization.

20782081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 20782081 is about 4558.7367767837. The cubic root of 20782081 is about 274.9347768184.

The spelling of 20782081 in words is "twenty million, seven hundred eighty-two thousand, eighty-one".