214221991 has 2 divisors, whose sum is σ = 214221992. Its totient is φ = 214221990.

The previous prime is 214221989. The next prime is 214222003. The reversal of 214221991 is 199122412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 214221991 - 2¹ = 214221989 is a prime.

It is a super-2 number, since 2×214221991² = 91782122856008162, which contains 22 as substring.

Together with 214221989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (214221961) 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, 107110995 + 107110996.

It is an arithmetic number, because the mean of its divisors is an integer number (107110996).

Almost surely, 2^214221991 is an apocalyptic number.

214221991 is a deficient number, since it is larger than the sum of its proper divisors (1).

214221991 is an equidigital number, since it uses as much as digits as its factorization.

214221991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 214221991 is about 14636.3243678186. The cubic root of 214221991 is about 598.3491574006.

The spelling of 214221991 in words is "two hundred fourteen million, two hundred twenty-one thousand, nine hundred ninety-one".