81495649 has 2 divisors, whose sum is σ = 81495650. Its totient is φ = 81495648.

The previous prime is 81495643. The next prime is 81495677. The reversal of 81495649 is 94659418.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73616400 + 7879249 = 8580^2 + 2807^2 .

It is a cyclic number.

It is not a de Polignac number, because 81495649 - 2⁹ = 81495137 is a prime.

It is a super-3 number, since 3×81495649³ (a number of 25 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81495599 and 81495608.

It is not a weakly prime, because it can be changed into another prime (81495643) 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, 40747824 + 40747825.

It is an arithmetic number, because the mean of its divisors is an integer number (40747825).

Almost surely, 2^81495649 is an apocalyptic number.

It is an amenable number.

81495649 is a deficient number, since it is larger than the sum of its proper divisors (1).

81495649 is an equidigital number, since it uses as much as digits as its factorization.

81495649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 46.

The square root of 81495649 is about 9027.4940598153. The cubic root of 81495649 is about 433.5556074005. Note that the first 3 decimals are identical.

The spelling of 81495649 in words is "eighty-one million, four hundred ninety-five thousand, six hundred forty-nine".