91811261 has 2 divisors, whose sum is σ = 91811262. Its totient is φ = 91811260.

The previous prime is 91811227. The next prime is 91811309. The reversal of 91811261 is 16211819.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54479161 + 37332100 = 7381^2 + 6110^2 .

It is a cyclic number.

It is not a de Polignac number, because 91811261 - 2¹⁰ = 91810237 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 (91811201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45905630 + 45905631.

It is an arithmetic number, because the mean of its divisors is an integer number (45905631).

Almost surely, 2^91811261 is an apocalyptic number.

It is an amenable number.

91811261 is a deficient number, since it is larger than the sum of its proper divisors (1).

91811261 is an equidigital number, since it uses as much as digits as its factorization.

91811261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 29.

The square root of 91811261 is about 9581.8192948938. The cubic root of 91811261 is about 451.1268237553.

The spelling of 91811261 in words is "ninety-one million, eight hundred eleven thousand, two hundred sixty-one".