81912323 has 4 divisors (see below), whose sum is σ = 84554688. Its totient is φ = 79269960.

The previous prime is 81912319. The next prime is 81912349. The reversal of 81912323 is 32321918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81912323 - 2² = 81912319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81914323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1321136 + ... + 1321197.

It is an arithmetic number, because the mean of its divisors is an integer number (21138672).

Almost surely, 2^81912323 is an apocalyptic number.

81912323 is a deficient number, since it is larger than the sum of its proper divisors (2642365).

81912323 is a wasteful number, since it uses less digits than its factorization.

81912323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2642364.

The product of its digits is 2592, while the sum is 29.

The square root of 81912323 is about 9050.5426909109. The cubic root of 81912323 is about 434.2932514449.

The spelling of 81912323 in words is "eighty-one million, nine hundred twelve thousand, three hundred twenty-three".