81149855 has 16 divisors (see below), whose sum is σ = 102799200. Its totient is φ = 61326720.

The previous prime is 81149851. The next prime is 81149867. The reversal of 81149855 is 55894118.

It is not a de Polignac number, because 81149855 - 2² = 81149851 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81149851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38981 + ... + 41009.

It is an arithmetic number, because the mean of its divisors is an integer number (6424950).

Almost surely, 2^81149855 is an apocalyptic number.

81149855 is a deficient number, since it is larger than the sum of its proper divisors (21649345).

81149855 is a wasteful number, since it uses less digits than its factorization.

81149855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2474.

The product of its digits is 57600, while the sum is 41.

The square root of 81149855 is about 9008.3214307661. The cubic root of 81149855 is about 432.9415317868.

The spelling of 81149855 in words is "eighty-one million, one hundred forty-nine thousand, eight hundred fifty-five".