81108993 has 16 divisors (see below), whose sum is σ = 124986240. Its totient is φ = 45826176.

The previous prime is 81108991. The next prime is 81109001. The reversal of 81108993 is 39980118.

It is a happy number.

It is not a de Polignac number, because 81108993 - 2¹ = 81108991 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81108991) 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, 19830 + ... + 23567.

It is an arithmetic number, because the mean of its divisors is an integer number (7811640).

Almost surely, 2^81108993 is an apocalyptic number.

It is an amenable number.

81108993 is a deficient number, since it is larger than the sum of its proper divisors (43877247).

81108993 is a wasteful number, since it uses less digits than its factorization.

81108993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43496.

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 81108993 is about 9006.0531310891. The cubic root of 81108993 is about 432.8688521456.

The spelling of 81108993 in words is "eighty-one million, one hundred eight thousand, nine hundred ninety-three".