91083221 has 2 divisors, whose sum is σ = 91083222. Its totient is φ = 91083220.

The previous prime is 91083191. The next prime is 91083241. The reversal of 91083221 is 12238019.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90459121 + 624100 = 9511^2 + 790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91083221 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91083241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45541610 + 45541611.

It is an arithmetic number, because the mean of its divisors is an integer number (45541611).

Almost surely, 2^91083221 is an apocalyptic number.

It is an amenable number.

91083221 is a deficient number, since it is larger than the sum of its proper divisors (1).

91083221 is an equidigital number, since it uses as much as digits as its factorization.

91083221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 91083221 is about 9543.7529829727. The cubic root of 91083221 is about 449.9312174707.

The spelling of 91083221 in words is "ninety-one million, eighty-three thousand, two hundred twenty-one".