81800089 has 4 divisors (see below), whose sum is σ = 93485824. Its totient is φ = 70114356.

The previous prime is 81800071. The next prime is 81800093. The reversal of 81800089 is 98000818.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81800089 - 2⁵ = 81800057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81800689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5842857 + ... + 5842870.

It is an arithmetic number, because the mean of its divisors is an integer number (23371456).

Almost surely, 2^81800089 is an apocalyptic number.

It is an amenable number.

81800089 is a deficient number, since it is larger than the sum of its proper divisors (11685735).

81800089 is a wasteful number, since it uses less digits than its factorization.

81800089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11685734.

The product of its (nonzero) digits is 4608, while the sum is 34.

The square root of 81800089 is about 9044.3401638815. The cubic root of 81800089 is about 434.0948085822.

The spelling of 81800089 in words is "eighty-one million, eight hundred thousand, eighty-nine".