91135973 has 2 divisors, whose sum is σ = 91135974. Its totient is φ = 91135972.

The previous prime is 91135949. The next prime is 91136011. The reversal of 91135973 is 37953119.

It is an a-pointer prime, because the next prime (91136011) can be obtained adding 91135973 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89453764 + 1682209 = 9458^2 + 1297^2 .

It is an emirp because it is prime and its reverse (37953119) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91135973 - 2¹⁸ = 90873829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91135903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45567986 + 45567987.

It is an arithmetic number, because the mean of its divisors is an integer number (45567987).

Almost surely, 2^91135973 is an apocalyptic number.

It is an amenable number.

91135973 is a deficient number, since it is larger than the sum of its proper divisors (1).

91135973 is an equidigital number, since it uses as much as digits as its factorization.

91135973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25515, while the sum is 38.

The square root of 91135973 is about 9546.5162755845. The cubic root of 91135973 is about 450.0180618265.

The spelling of 91135973 in words is "ninety-one million, one hundred thirty-five thousand, nine hundred seventy-three".