91584221 has 2 divisors, whose sum is σ = 91584222. Its totient is φ = 91584220.

The previous prime is 91584217. The next prime is 91584239. The reversal of 91584221 is 12248519.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61058596 + 30525625 = 7814^2 + 5525^2 .

It is an emirp because it is prime and its reverse (12248519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91584221 - 2² = 91584217 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 (91584211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45792110 + 45792111.

It is an arithmetic number, because the mean of its divisors is an integer number (45792111).

Almost surely, 2^91584221 is an apocalyptic number.

It is an amenable number.

91584221 is a deficient number, since it is larger than the sum of its proper divisors (1).

91584221 is an equidigital number, since it uses as much as digits as its factorization.

91584221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 91584221 is about 9569.9645244902. The cubic root of 91584221 is about 450.7546530757.

The spelling of 91584221 in words is "ninety-one million, five hundred eighty-four thousand, two hundred twenty-one".