91367821 has 2 divisors, whose sum is σ = 91367822. Its totient is φ = 91367820.

The previous prime is 91367797. The next prime is 91367839. The reversal of 91367821 is 12876319.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75255625 + 16112196 = 8675^2 + 4014^2 .

It is a cyclic number.

It is not a de Polignac number, because 91367821 - 2⁷ = 91367693 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 (91367021) 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, 45683910 + 45683911.

It is an arithmetic number, because the mean of its divisors is an integer number (45683911).

Almost surely, 2^91367821 is an apocalyptic number.

It is an amenable number.

91367821 is a deficient number, since it is larger than the sum of its proper divisors (1).

91367821 is an equidigital number, since it uses as much as digits as its factorization.

91367821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 37.

The square root of 91367821 is about 9558.6516308525. The cubic root of 91367821 is about 450.3993508425.

The spelling of 91367821 in words is "ninety-one million, three hundred sixty-seven thousand, eight hundred twenty-one".