81457133 has 2 divisors, whose sum is σ = 81457134. Its totient is φ = 81457132.

The previous prime is 81457127. The next prime is 81457139. The reversal of 81457133 is 33175418.

It is a balanced prime because it is at equal distance from previous prime (81457127) and next prime (81457139).

It can be written as a sum of positive squares in only one way, i.e., 71859529 + 9597604 = 8477^2 + 3098^2 .

It is a cyclic number.

It is not a de Polignac number, because 81457133 - 2⁶ = 81457069 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81457133.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81457139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40728566 + 40728567.

It is an arithmetic number, because the mean of its divisors is an integer number (40728567).

Almost surely, 2^81457133 is an apocalyptic number.

It is an amenable number.

81457133 is a deficient number, since it is larger than the sum of its proper divisors (1).

81457133 is an equidigital number, since it uses as much as digits as its factorization.

81457133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 32.

The square root of 81457133 is about 9025.3605468147. The cubic root of 81457133 is about 433.4872951271.

The spelling of 81457133 in words is "eighty-one million, four hundred fifty-seven thousand, one hundred thirty-three".