91428581 has 2 divisors, whose sum is σ = 91428582. Its totient is φ = 91428580.

The previous prime is 91428541. The next prime is 91428587. The reversal of 91428581 is 18582419.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65060356 + 26368225 = 8066^2 + 5135^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91428581 is a prime.

It is a super-2 number, since 2×91428581² = 16718370847347122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91428587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45714290 + 45714291.

It is an arithmetic number, because the mean of its divisors is an integer number (45714291).

Almost surely, 2^91428581 is an apocalyptic number.

It is an amenable number.

91428581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91428581 is an equidigital number, since it uses as much as digits as its factorization.

91428581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23040, while the sum is 38.

The square root of 91428581 is about 9561.8293751771. The cubic root of 91428581 is about 450.4991678980.

The spelling of 91428581 in words is "ninety-one million, four hundred twenty-eight thousand, five hundred eighty-one".