21801163 has 2 divisors, whose sum is σ = 21801164. Its totient is φ = 21801162.

The previous prime is 21801161. The next prime is 21801181. The reversal of 21801163 is 36110812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21801163 - 2¹ = 21801161 is a prime.

Together with 21801161, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21801161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10900581 + 10900582.

It is an arithmetic number, because the mean of its divisors is an integer number (10900582).

Almost surely, 2^21801163 is an apocalyptic number.

21801163 is a deficient number, since it is larger than the sum of its proper divisors (1).

21801163 is an equidigital number, since it uses as much as digits as its factorization.

21801163 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 21801163 is about 4669.1715539269. The cubic root of 21801163 is about 279.3572117224.

Adding to 21801163 its reverse (36110812), we get a palindrome (57911975).

The spelling of 21801163 in words is "twenty-one million, eight hundred one thousand, one hundred sixty-three".