221208971 has 2 divisors, whose sum is σ = 221208972. Its totient is φ = 221208970.

The previous prime is 221208961. The next prime is 221208973. The reversal of 221208971 is 179802122.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221208971 - 2¹⁰ = 221207947 is a prime.

Together with 221208973, 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 (221208973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110604485 + 110604486.

It is an arithmetic number, because the mean of its divisors is an integer number (110604486).

Almost surely, 2^221208971 is an apocalyptic number.

221208971 is a deficient number, since it is larger than the sum of its proper divisors (1).

221208971 is an equidigital number, since it uses as much as digits as its factorization.

221208971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 221208971 is about 14873.0955419509. The cubic root of 221208971 is about 604.7848616931.

The spelling of 221208971 in words is "two hundred twenty-one million, two hundred eight thousand, nine hundred seventy-one".