81912433 has 4 divisors (see below), whose sum is σ = 81931888. Its totient is φ = 81892980.

The previous prime is 81912427. The next prime is 81912449. The reversal of 81912433 is 33421918.

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, and also an emirpimes, since its reverse is a distinct semiprime: 33421918 = 2 ⋅16710959.

It is a cyclic number.

It is not a de Polignac number, because 81912433 - 2¹⁷ = 81781361 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81912395 and 81912404.

It is not an unprimeable number, because it can be changed into a prime (81912533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 483 + ... + 12808.

It is an arithmetic number, because the mean of its divisors is an integer number (20482972).

Almost surely, 2^81912433 is an apocalyptic number.

It is an amenable number.

81912433 is a deficient number, since it is larger than the sum of its proper divisors (19455).

81912433 is a wasteful number, since it uses less digits than its factorization.

81912433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19454.

The product of its digits is 5184, while the sum is 31.

The square root of 81912433 is about 9050.5487678925. The cubic root of 81912433 is about 434.2934458488.

The spelling of 81912433 in words is "eighty-one million, nine hundred twelve thousand, four hundred thirty-three".