81369091 has 2 divisors, whose sum is σ = 81369092. Its totient is φ = 81369090.

The previous prime is 81369047. The next prime is 81369097. The reversal of 81369091 is 19096318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81369091 - 2¹¹ = 81367043 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81369091.

It is not a weakly prime, because it can be changed into another prime (81369097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40684545 + 40684546.

It is an arithmetic number, because the mean of its divisors is an integer number (40684546).

Almost surely, 2^81369091 is an apocalyptic number.

81369091 is a deficient number, since it is larger than the sum of its proper divisors (1).

81369091 is an equidigital number, since it uses as much as digits as its factorization.

81369091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 81369091 is about 9020.4817498845. The cubic root of 81369091 is about 433.3310622498.

The spelling of 81369091 in words is "eighty-one million, three hundred sixty-nine thousand, ninety-one".