81487666 has 32 divisors (see below), whose sum is σ = 140595840. Its totient is φ = 35126784.

The previous prime is 81487649. The next prime is 81487687. The reversal of 81487666 is 66678418.

It is a happy number.

It is a super-3 number, since 3×81487666³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24130 + ... + 27298.

It is an arithmetic number, because the mean of its divisors is an integer number (4393620).

Almost surely, 2^81487666 is an apocalyptic number.

81487666 is a gapful number since it is divisible by the number (86) formed by its first and last digit.

81487666 is a deficient number, since it is larger than the sum of its proper divisors (59108174).

81487666 is a wasteful number, since it uses less digits than its factorization.

81487666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3250.

The product of its digits is 387072, while the sum is 46.

The square root of 81487666 is about 9027.0518997068. The cubic root of 81487666 is about 433.5414504589.

The spelling of 81487666 in words is "eighty-one million, four hundred eighty-seven thousand, six hundred sixty-six".