221677891 has 2 divisors, whose sum is σ = 221677892. Its totient is φ = 221677890.

The previous prime is 221677889. The next prime is 221677901. The reversal of 221677891 is 198776122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221677891 - 2¹ = 221677889 is a prime.

Together with 221677889, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (221677801) 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, 110838945 + 110838946.

It is an arithmetic number, because the mean of its divisors is an integer number (110838946).

Almost surely, 2^221677891 is an apocalyptic number.

221677891 is a deficient number, since it is larger than the sum of its proper divisors (1).

221677891 is an equidigital number, since it uses as much as digits as its factorization.

221677891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 43.

The square root of 221677891 is about 14888.8512317103. The cubic root of 221677891 is about 605.2119021855.

The spelling of 221677891 in words is "two hundred twenty-one million, six hundred seventy-seven thousand, eight hundred ninety-one".