21828841 has 2 divisors, whose sum is σ = 21828842. Its totient is φ = 21828840.

The previous prime is 21828839. The next prime is 21828847. The reversal of 21828841 is 14882812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21196816 + 632025 = 4604^2 + 795^2 .

It is a cyclic number.

It is not a de Polignac number, because 21828841 - 2¹ = 21828839 is a prime.

It is a super-3 number, since 3×21828841³ (a number of 23 digits) contains 333 as substring.

Together with 21828839, it forms a pair of twin primes.

It is equal to p_1379095 and since 21828841 and 1379095 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21828797 and 21828806.

It is not a weakly prime, because it can be changed into another prime (21828847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10914420 + 10914421.

It is an arithmetic number, because the mean of its divisors is an integer number (10914421).

Almost surely, 2^21828841 is an apocalyptic number.

It is an amenable number.

21828841 is a deficient number, since it is larger than the sum of its proper divisors (1).

21828841 is an equidigital number, since it uses as much as digits as its factorization.

21828841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8192, while the sum is 34.

The square root of 21828841 is about 4672.1345228921. The cubic root of 21828841 is about 279.4753824685.

The spelling of 21828841 in words is "twenty-one million, eight hundred twenty-eight thousand, eight hundred forty-one".