20884861 has 2 divisors, whose sum is σ = 20884862. Its totient is φ = 20884860.

The previous prime is 20884859. The next prime is 20884907. The reversal of 20884861 is 16848802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14584761 + 6300100 = 3819^2 + 2510^2 .

It is a cyclic number.

It is not a de Polignac number, because 20884861 - 2¹ = 20884859 is a prime.

Together with 20884859, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20884861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20884811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10442430 + 10442431.

It is an arithmetic number, because the mean of its divisors is an integer number (10442431).

Almost surely, 2^20884861 is an apocalyptic number.

It is an amenable number.

20884861 is a deficient number, since it is larger than the sum of its proper divisors (1).

20884861 is an equidigital number, since it uses as much as digits as its factorization.

20884861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24576, while the sum is 37.

The square root of 20884861 is about 4569.9957330396. The cubic root of 20884861 is about 275.3872714451.

The spelling of 20884861 in words is "twenty million, eight hundred eighty-four thousand, eight hundred sixty-one".