81248591 has 2 divisors, whose sum is σ = 81248592. Its totient is φ = 81248590.

The previous prime is 81248569. The next prime is 81248597. The reversal of 81248591 is 19584218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81248591 - 2⁶ = 81248527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81248597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40624295 + 40624296.

It is an arithmetic number, because the mean of its divisors is an integer number (40624296).

Almost surely, 2^81248591 is an apocalyptic number.

81248591 is a deficient number, since it is larger than the sum of its proper divisors (1).

81248591 is an equidigital number, since it uses as much as digits as its factorization.

81248591 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 81248591 is about 9013.8000310635. The cubic root of 81248591 is about 433.1170490029.

The spelling of 81248591 in words is "eighty-one million, two hundred forty-eight thousand, five hundred ninety-one".