21699211 has 2 divisors, whose sum is σ = 21699212. Its totient is φ = 21699210.

The previous prime is 21699203. The next prime is 21699229. The reversal of 21699211 is 11299612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21699211 - 2³ = 21699203 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21699011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10849605 + 10849606.

It is an arithmetic number, because the mean of its divisors is an integer number (10849606).

Almost surely, 2^21699211 is an apocalyptic number.

21699211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21699211 is an equidigital number, since it uses as much as digits as its factorization.

21699211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 31.

The square root of 21699211 is about 4658.2411916946. The cubic root of 21699211 is about 278.9210646717.

The spelling of 21699211 in words is "twenty-one million, six hundred ninety-nine thousand, two hundred eleven".