91279421 has 2 divisors, whose sum is σ = 91279422. Its totient is φ = 91279420.

The previous prime is 91279403. The next prime is 91279423. The reversal of 91279421 is 12497219.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 89510521 + 1768900 = 9461^2 + 1330^2 .

It is a cyclic number.

It is not a de Polignac number, because 91279421 - 2¹⁴ = 91263037 is a prime.

Together with 91279423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91279423) 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, 45639710 + 45639711.

It is an arithmetic number, because the mean of its divisors is an integer number (45639711).

Almost surely, 2^91279421 is an apocalyptic number.

It is an amenable number.

91279421 is a deficient number, since it is larger than the sum of its proper divisors (1).

91279421 is an equidigital number, since it uses as much as digits as its factorization.

91279421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 35.

The square root of 91279421 is about 9554.0264286844. The cubic root of 91279421 is about 450.2540474970.

The spelling of 91279421 in words is "ninety-one million, two hundred seventy-nine thousand, four hundred twenty-one".