221391189 has 12 divisors (see below), whose sum is σ = 320928972. Its totient is φ = 147067200.

The previous prime is 221391167. The next prime is 221391199. The reversal of 221391189 is 981193122.

It can be written as a sum of positive squares in 2 ways, for example, as 124211025 + 97180164 = 11145^2 + 9858^2 .

It is not a de Polignac number, because 221391189 - 2¹² = 221387093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221391109) 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 in 11 ways as a sum of consecutive naturals, for example, 41242 + ... + 46299.

It is an arithmetic number, because the mean of its divisors is an integer number (26744081).

Almost surely, 2^221391189 is an apocalyptic number.

It is an amenable number.

221391189 is a deficient number, since it is larger than the sum of its proper divisors (99537783).

221391189 is a wasteful number, since it uses less digits than its factorization.

221391189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87828 (or 87825 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 221391189 is about 14879.2200400424. The cubic root of 221391189 is about 604.9508773266.

The spelling of 221391189 in words is "two hundred twenty-one million, three hundred ninety-one thousand, one hundred eighty-nine".