91991441 has 2 divisors, whose sum is σ = 91991442. Its totient is φ = 91991440.

The previous prime is 91991401. The next prime is 91991453. The reversal of 91991441 is 14419919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78145600 + 13845841 = 8840^2 + 3721^2 .

It is a cyclic number.

It is not a de Polignac number, because 91991441 - 2¹⁴ = 91975057 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 91991395 and 91991404.

It is not a weakly prime, because it can be changed into another prime (91991401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45995720 + 45995721.

It is an arithmetic number, because the mean of its divisors is an integer number (45995721).

Almost surely, 2^91991441 is an apocalyptic number.

It is an amenable number.

91991441 is a deficient number, since it is larger than the sum of its proper divisors (1).

91991441 is an equidigital number, since it uses as much as digits as its factorization.

91991441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 38.

The square root of 91991441 is about 9591.2168675304. The cubic root of 91991441 is about 451.4217436983.

The spelling of 91991441 in words is "ninety-one million, nine hundred ninety-one thousand, four hundred forty-one".