21698203 has 2 divisors, whose sum is σ = 21698204. Its totient is φ = 21698202.

The previous prime is 21698191. The next prime is 21698207. The reversal of 21698203 is 30289612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21698203 is a prime.

It is not a weakly prime, because it can be changed into another prime (21698207) 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, 10849101 + 10849102.

It is an arithmetic number, because the mean of its divisors is an integer number (10849102).

Almost surely, 2^21698203 is an apocalyptic number.

21698203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21698203 is an equidigital number, since it uses as much as digits as its factorization.

21698203 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 21698203 is about 4658.1329950958. The cubic root of 21698203 is about 278.9167456700.

The spelling of 21698203 in words is "twenty-one million, six hundred ninety-eight thousand, two hundred three".