81109155 has 16 divisors (see below), whose sum is σ = 135417600. Its totient is φ = 41377248.

The previous prime is 81109151. The next prime is 81109187. The reversal of 81109155 is 55190118.

It is not a de Polignac number, because 81109155 - 2² = 81109151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81109151) 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, 117205 + ... + 117894.

It is an arithmetic number, because the mean of its divisors is an integer number (8463600).

Almost surely, 2^81109155 is an apocalyptic number.

81109155 is a deficient number, since it is larger than the sum of its proper divisors (54308445).

81109155 is a wasteful number, since it uses less digits than its factorization.

81109155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235130.

The product of its (nonzero) digits is 1800, while the sum is 30.

The square root of 81109155 is about 9006.0621250356. The cubic root of 81109155 is about 432.8691403368.

The spelling of 81109155 in words is "eighty-one million, one hundred nine thousand, one hundred fifty-five".