91561471 has 2 divisors, whose sum is σ = 91561472. Its totient is φ = 91561470.

The previous prime is 91561447. The next prime is 91561511. The reversal of 91561471 is 17416519.

It is a weak prime.

It is an emirp because it is prime and its reverse (17416519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91561471 - 2²⁵ = 58007039 is a prime.

It is a super-3 number, since 3×91561471³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91561411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45780735 + 45780736.

It is an arithmetic number, because the mean of its divisors is an integer number (45780736).

Almost surely, 2^91561471 is an apocalyptic number.

91561471 is a deficient number, since it is larger than the sum of its proper divisors (1).

91561471 is an equidigital number, since it uses as much as digits as its factorization.

91561471 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 34.

The square root of 91561471 is about 9568.7758360200. The cubic root of 91561471 is about 450.7173267129.

The spelling of 91561471 in words is "ninety-one million, five hundred sixty-one thousand, four hundred seventy-one".