81047855 has 16 divisors (see below), whose sum is σ = 111365184. Its totient is φ = 55468800.

The previous prime is 81047831. The next prime is 81047861. The reversal of 81047855 is 55874018.

81047855 = T₁₈₉ + T₁₉₀ + ... + T₇₈₉.

It is not a de Polignac number, because 81047855 - 2¹⁴ = 81031471 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

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, 19109 + ... + 22961.

It is an arithmetic number, because the mean of its divisors is an integer number (6960324).

Almost surely, 2^81047855 is an apocalyptic number.

81047855 is a deficient number, since it is larger than the sum of its proper divisors (30317329).

81047855 is a wasteful number, since it uses less digits than its factorization.

81047855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4466.

The product of its (nonzero) digits is 44800, while the sum is 38.

The square root of 81047855 is about 9002.6582185486. The cubic root of 81047855 is about 432.7600627780.

The spelling of 81047855 in words is "eighty-one million, forty-seven thousand, eight hundred fifty-five".