21118841 has 2 divisors, whose sum is σ = 21118842. Its totient is φ = 21118840.

The previous prime is 21118829. The next prime is 21118847. The reversal of 21118841 is 14881112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19669225 + 1449616 = 4435^2 + 1204^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21118841 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21118841.

It is not a weakly prime, because it can be changed into another prime (21118847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10559420 + 10559421.

It is an arithmetic number, because the mean of its divisors is an integer number (10559421).

Almost surely, 2^21118841 is an apocalyptic number.

It is an amenable number.

21118841 is a deficient number, since it is larger than the sum of its proper divisors (1).

21118841 is an equidigital number, since it uses as much as digits as its factorization.

21118841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 512, while the sum is 26.

The square root of 21118841 is about 4595.5240179984. The cubic root of 21118841 is about 276.4118728071.

Adding to 21118841 its reverse (14881112), we get a palindrome (35999953).

The spelling of 21118841 in words is "twenty-one million, one hundred eighteen thousand, eight hundred forty-one".