21813163 has 2 divisors, whose sum is σ = 21813164. Its totient is φ = 21813162.

The previous prime is 21813101. The next prime is 21813179. The reversal of 21813163 is 36131812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21813163 - 2¹³ = 21804971 is a prime.

It is not a weakly prime, because it can be changed into another prime (21813563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906581 + 10906582.

It is an arithmetic number, because the mean of its divisors is an integer number (10906582).

Almost surely, 2^21813163 is an apocalyptic number.

21813163 is a deficient number, since it is larger than the sum of its proper divisors (1).

21813163 is an equidigital number, since it uses as much as digits as its factorization.

21813163 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 25.

The square root of 21813163 is about 4670.4564016807. The cubic root of 21813163 is about 279.4084577906.

Adding to 21813163 its reverse (36131812), we get a palindrome (57944975).

The spelling of 21813163 in words is "twenty-one million, eight hundred thirteen thousand, one hundred sixty-three".