221288189 has 2 divisors, whose sum is σ = 221288190. Its totient is φ = 221288188.

The previous prime is 221288153. The next prime is 221288219. The reversal of 221288189 is 981882122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200448964 + 20839225 = 14158^2 + 4565^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221288189 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221288489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110644094 + 110644095.

It is an arithmetic number, because the mean of its divisors is an integer number (110644095).

Almost surely, 2^221288189 is an apocalyptic number.

It is an amenable number.

221288189 is a deficient number, since it is larger than the sum of its proper divisors (1).

221288189 is an equidigital number, since it uses as much as digits as its factorization.

221288189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36864, while the sum is 41.

The square root of 221288189 is about 14875.7584344463. The cubic root of 221288189 is about 604.8570470254.

The spelling of 221288189 in words is "two hundred twenty-one million, two hundred eighty-eight thousand, one hundred eighty-nine".