81240866 has 16 divisors (see below), whose sum is σ = 139496640. Its totient is φ = 34760880.

The previous prime is 81240857. The next prime is 81240871. The reversal of 81240866 is 66804218.

It is a super-3 number, since 3×81240866³ (a number of 25 digits) contains 333 as substring.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 4865 + ... + 13643.

It is an arithmetic number, because the mean of its divisors is an integer number (8718540).

Almost surely, 2^81240866 is an apocalyptic number.

81240866 is a deficient number, since it is larger than the sum of its proper divisors (58255774).

81240866 is a wasteful number, since it uses less digits than its factorization.

81240866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9449.

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 81240866 is about 9013.3715112604. The cubic root of 81240866 is about 433.1033218510.

The spelling of 81240866 in words is "eighty-one million, two hundred forty thousand, eight hundred sixty-six".