81066439 has 4 divisors (see below), whose sum is σ = 81236160. Its totient is φ = 80896720.

The previous prime is 81066409. The next prime is 81066473. The reversal of 81066439 is 93466018.

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 81066439 - 2¹¹ = 81064391 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81066398 and 81066407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81066409) 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, 84142 + ... + 85099.

It is an arithmetic number, because the mean of its divisors is an integer number (20309040).

Almost surely, 2^81066439 is an apocalyptic number.

81066439 is a deficient number, since it is larger than the sum of its proper divisors (169721).

81066439 is a wasteful number, since it uses less digits than its factorization.

81066439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169720.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 81066439 is about 9003.6902989830. The cubic root of 81066439 is about 432.7931370581.

The spelling of 81066439 in words is "eighty-one million, sixty-six thousand, four hundred thirty-nine".