91145321 has 2 divisors, whose sum is σ = 91145322. Its totient is φ = 91145320.

The previous prime is 91145317. The next prime is 91145323. The reversal of 91145321 is 12354119.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66504025 + 24641296 = 8155^2 + 4964^2 .

It is a cyclic number.

It is not a de Polignac number, because 91145321 - 2² = 91145317 is a prime.

Together with 91145323, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91145323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45572660 + 45572661.

It is an arithmetic number, because the mean of its divisors is an integer number (45572661).

Almost surely, 2^91145321 is an apocalyptic number.

It is an amenable number.

91145321 is a deficient number, since it is larger than the sum of its proper divisors (1).

91145321 is an equidigital number, since it uses as much as digits as its factorization.

91145321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 26.

The square root of 91145321 is about 9547.0058657152. The cubic root of 91145321 is about 450.0334477196.

The spelling of 91145321 in words is "ninety-one million, one hundred forty-five thousand, three hundred twenty-one".