221933891 has 2 divisors, whose sum is σ = 221933892. Its totient is φ = 221933890.

The previous prime is 221933849. The next prime is 221933893. The reversal of 221933891 is 198339122.

221933891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221933891 is a prime.

Together with 221933893, 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 (221933893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110966945 + 110966946.

It is an arithmetic number, because the mean of its divisors is an integer number (110966946).

Almost surely, 2^221933891 is an apocalyptic number.

221933891 is a deficient number, since it is larger than the sum of its proper divisors (1).

221933891 is an equidigital number, since it uses as much as digits as its factorization.

221933891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 38.

The square root of 221933891 is about 14897.4457877852. The cubic root of 221933891 is about 605.4447845953. Note that the first 3 decimals are identical.

The spelling of 221933891 in words is "two hundred twenty-one million, nine hundred thirty-three thousand, eight hundred ninety-one".