91804421 has 2 divisors, whose sum is σ = 91804422. Its totient is φ = 91804420.

The previous prime is 91804397. The next prime is 91804429. The reversal of 91804421 is 12440819.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90516196 + 1288225 = 9514^2 + 1135^2 .

It is an emirp because it is prime and its reverse (12440819) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91804421 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 (91804429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45902210 + 45902211.

It is an arithmetic number, because the mean of its divisors is an integer number (45902211).

Almost surely, 2^91804421 is an apocalyptic number.

It is an amenable number.

91804421 is a deficient number, since it is larger than the sum of its proper divisors (1).

91804421 is an equidigital number, since it uses as much as digits as its factorization.

91804421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 91804421 is about 9581.4623622911. The cubic root of 91804421 is about 451.1156203943.

The spelling of 91804421 in words is "ninety-one million, eight hundred four thousand, four hundred twenty-one".