21996841 has 2 divisors, whose sum is σ = 21996842. Its totient is φ = 21996840.

The previous prime is 21996817. The next prime is 21996853. The reversal of 21996841 is 14869912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20025625 + 1971216 = 4475^2 + 1404^2 .

It is a cyclic number.

It is not a de Polignac number, because 21996841 - 2¹³ = 21988649 is a prime.

It is a super-2 number, since 2×21996841² = 967722027958562, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21996794 and 21996803.

It is not a weakly prime, because it can be changed into another prime (21996881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10998420 + 10998421.

It is an arithmetic number, because the mean of its divisors is an integer number (10998421).

Almost surely, 2^21996841 is an apocalyptic number.

It is an amenable number.

21996841 is a deficient number, since it is larger than the sum of its proper divisors (1).

21996841 is an equidigital number, since it uses as much as digits as its factorization.

21996841 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 40.

The square root of 21996841 is about 4690.0789972025. The cubic root of 21996841 is about 280.1905208444.

The spelling of 21996841 in words is "twenty-one million, nine hundred ninety-six thousand, eight hundred forty-one".