21098171 has 2 divisors, whose sum is σ = 21098172. Its totient is φ = 21098170.

The previous prime is 21098141. The next prime is 21098183. The reversal of 21098171 is 17189012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21098171 - 2¹⁴ = 21081787 is a prime.

It is not a weakly prime, because it can be changed into another prime (21098111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549085 + 10549086.

It is an arithmetic number, because the mean of its divisors is an integer number (10549086).

Almost surely, 2^21098171 is an apocalyptic number.

21098171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21098171 is an equidigital number, since it uses as much as digits as its factorization.

21098171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 21098171 is about 4593.2745400204. The cubic root of 21098171 is about 276.3216642831.

The spelling of 21098171 in words is "twenty-one million, ninety-eight thousand, one hundred seventy-one".