91089221 has 2 divisors, whose sum is σ = 91089222. Its totient is φ = 91089220.

The previous prime is 91089209. The next prime is 91089277. The reversal of 91089221 is 12298019.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65788321 + 25300900 = 8111^2 + 5030^2 .

It is a cyclic number.

It is not a de Polignac number, because 91089221 - 2¹⁰ = 91088197 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 (91089121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45544610 + 45544611.

It is an arithmetic number, because the mean of its divisors is an integer number (45544611).

Almost surely, 2^91089221 is an apocalyptic number.

It is an amenable number.

91089221 is a deficient number, since it is larger than the sum of its proper divisors (1).

91089221 is an equidigital number, since it uses as much as digits as its factorization.

91089221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 91089221 is about 9544.0673195446. The cubic root of 91089221 is about 449.9410968169.

The spelling of 91089221 in words is "ninety-one million, eighty-nine thousand, two hundred twenty-one".