81548689 has 2 divisors, whose sum is σ = 81548690. Its totient is φ = 81548688.

The previous prime is 81548681. The next prime is 81548723. The reversal of 81548689 is 98684518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54508689 + 27040000 = 7383^2 + 5200^2 .

It is a cyclic number.

It is not a de Polignac number, because 81548689 - 2³ = 81548681 is a prime.

It is not a weakly prime, because it can be changed into another prime (81548681) 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, 40774344 + 40774345.

It is an arithmetic number, because the mean of its divisors is an integer number (40774345).

Almost surely, 2^81548689 is an apocalyptic number.

It is an amenable number.

81548689 is a deficient number, since it is larger than the sum of its proper divisors (1).

81548689 is an equidigital number, since it uses as much as digits as its factorization.

81548689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 552960, while the sum is 49.

The square root of 81548689 is about 9030.4312743080. The cubic root of 81548689 is about 433.6496443325.

The spelling of 81548689 in words is "eighty-one million, five hundred forty-eight thousand, six hundred eighty-nine".