221395871 has 2 divisors, whose sum is σ = 221395872. Its totient is φ = 221395870.

The previous prime is 221395843. The next prime is 221395903. The reversal of 221395871 is 178593122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221395871 - 2¹⁸ = 221133727 is a prime.

It is a super-2 number, since 2×221395871² = 98032263391697282, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221395571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110697935 + 110697936.

It is an arithmetic number, because the mean of its divisors is an integer number (110697936).

Almost surely, 2^221395871 is an apocalyptic number.

221395871 is a deficient number, since it is larger than the sum of its proper divisors (1).

221395871 is an equidigital number, since it uses as much as digits as its factorization.

221395871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 38.

The square root of 221395871 is about 14879.3773727263. The cubic root of 221395871 is about 604.9551418144.

The spelling of 221395871 in words is "two hundred twenty-one million, three hundred ninety-five thousand, eight hundred seventy-one".