81355349 has 2 divisors, whose sum is σ = 81355350. Its totient is φ = 81355348.

The previous prime is 81355331. The next prime is 81355363. The reversal of 81355349 is 94355318.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56175025 + 25180324 = 7495^2 + 5018^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81355349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81355649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40677674 + 40677675.

It is an arithmetic number, because the mean of its divisors is an integer number (40677675).

Almost surely, 2^81355349 is an apocalyptic number.

It is an amenable number.

81355349 is a deficient number, since it is larger than the sum of its proper divisors (1).

81355349 is an equidigital number, since it uses as much as digits as its factorization.

81355349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 38.

The square root of 81355349 is about 9019.7200067408. The cubic root of 81355349 is about 433.3066665378.

The spelling of 81355349 in words is "eighty-one million, three hundred fifty-five thousand, three hundred forty-nine".