91447789 has 2 divisors, whose sum is σ = 91447790. Its totient is φ = 91447788.

The previous prime is 91447781. The next prime is 91447813. The reversal of 91447789 is 98774419.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58293225 + 33154564 = 7635^2 + 5758^2 .

It is a cyclic number.

It is not a de Polignac number, because 91447789 - 2³ = 91447781 is a prime.

It is a super-2 number, since 2×91447789² = 16725396225977042, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91447781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45723894 + 45723895.

It is an arithmetic number, because the mean of its divisors is an integer number (45723895).

Almost surely, 2^91447789 is an apocalyptic number.

It is an amenable number.

91447789 is a deficient number, since it is larger than the sum of its proper divisors (1).

91447789 is an equidigital number, since it uses as much as digits as its factorization.

91447789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 49.

The square root of 91447789 is about 9562.8337327384. The cubic root of 91447789 is about 450.5307137670.

The spelling of 91447789 in words is "ninety-one million, four hundred forty-seven thousand, seven hundred eighty-nine".