81110023209 has 24 divisors (see below), whose sum is σ = 120032858400. Its totient is φ = 52747277760.

The previous prime is 81110023207. The next prime is 81110023219. The reversal of 81110023209 is 90232001118.

It is not a de Polignac number, because 81110023209 - 2¹ = 81110023207 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81110023207) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4647702 + ... + 4665120.

It is an arithmetic number, because the mean of its divisors is an integer number (5001369100).

Almost surely, 2^81110023209 is an apocalyptic number.

It is an amenable number.

81110023209 is a deficient number, since it is larger than the sum of its proper divisors (38922835191).

81110023209 is a wasteful number, since it uses less digits than its factorization.

81110023209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30085 (or 30082 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The spelling of 81110023209 in words is "eighty-one billion, one hundred ten million, twenty-three thousand, two hundred nine".