81081806 has 48 divisors (see below), whose sum is σ = 141826464. Its totient is φ = 34624512.

The previous prime is 81081779. The next prime is 81081817. The reversal of 81081806 is 60818018.

81081806 = T₄₁₀ + T₄₁₁ + ... + T₈₂₁.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 591770 + ... + 591906.

It is an arithmetic number, because the mean of its divisors is an integer number (2954718).

Almost surely, 2^81081806 is an apocalyptic number.

81081806 is a deficient number, since it is larger than the sum of its proper divisors (60744658).

81081806 is a wasteful number, since it uses less digits than its factorization.

81081806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285 (or 272 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 32.

The square root of 81081806 is about 9004.5436308566. The cubic root of 81081806 is about 432.8204821676.

The spelling of 81081806 in words is "eighty-one million, eighty-one thousand, eight hundred six".