21618341 has 2 divisors, whose sum is σ = 21618342. Its totient is φ = 21618340.

The previous prime is 21618319. The next prime is 21618349. The reversal of 21618341 is 14381612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19228225 + 2390116 = 4385^2 + 1546^2 .

It is a cyclic number.

It is not a de Polignac number, because 21618341 - 2⁶ = 21618277 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21618341.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21618349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10809170 + 10809171.

It is an arithmetic number, because the mean of its divisors is an integer number (10809171).

Almost surely, 2^21618341 is an apocalyptic number.

It is an amenable number.

21618341 is a deficient number, since it is larger than the sum of its proper divisors (1).

21618341 is an equidigital number, since it uses as much as digits as its factorization.

21618341 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 26.

The square root of 21618341 is about 4649.5527741924. The cubic root of 21618341 is about 278.5741330691.

Adding to 21618341 its reverse (14381612), we get a palindrome (35999953).

The spelling of 21618341 in words is "twenty-one million, six hundred eighteen thousand, three hundred forty-one".