21098771 has 2 divisors, whose sum is σ = 21098772. Its totient is φ = 21098770.

The previous prime is 21098731. The next prime is 21098773. The reversal of 21098771 is 17789012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21098771 - 2²² = 16904467 is a prime.

Together with 21098773, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21098773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549385 + 10549386.

It is an arithmetic number, because the mean of its divisors is an integer number (10549386).

Almost surely, 2^21098771 is an apocalyptic number.

21098771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21098771 is an equidigital number, since it uses as much as digits as its factorization.

21098771 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 21098771 is about 4593.3398524385. The cubic root of 21098771 is about 276.3242836480.

The spelling of 21098771 in words is "twenty-one million, ninety-eight thousand, seven hundred seventy-one".