21789241 has 2 divisors, whose sum is σ = 21789242. Its totient is φ = 21789240.

The previous prime is 21789233. The next prime is 21789281. The reversal of 21789241 is 14298712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21353641 + 435600 = 4621^2 + 660^2 .

It is a cyclic number.

It is not a de Polignac number, because 21789241 - 2³ = 21789233 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21789197 and 21789206.

It is not a weakly prime, because it can be changed into another prime (21789281) 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, 10894620 + 10894621.

It is an arithmetic number, because the mean of its divisors is an integer number (10894621).

Almost surely, 2^21789241 is an apocalyptic number.

It is an amenable number.

21789241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21789241 is an equidigital number, since it uses as much as digits as its factorization.

21789241 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 34.

The square root of 21789241 is about 4667.8947074672. The cubic root of 21789241 is about 279.3062801282.

The spelling of 21789241 in words is "twenty-one million, seven hundred eighty-nine thousand, two hundred forty-one".