81735839 has 4 divisors (see below), whose sum is σ = 82887120. Its totient is φ = 80584560.

The previous prime is 81735817. The next prime is 81735877. The reversal of 81735839 is 93853718.

It is a happy number.

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 81735839 - 2¹² = 81731743 is a prime.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 81735839.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81735889) 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, 575534 + ... + 575675.

It is an arithmetic number, because the mean of its divisors is an integer number (20721780).

Almost surely, 2^81735839 is an apocalyptic number.

81735839 is a deficient number, since it is larger than the sum of its proper divisors (1151281).

81735839 is a wasteful number, since it uses less digits than its factorization.

81735839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1151280.

The product of its digits is 181440, while the sum is 44.

The square root of 81735839 is about 9040.7875210072. The cubic root of 81735839 is about 433.9811253445.

The spelling of 81735839 in words is "eighty-one million, seven hundred thirty-five thousand, eight hundred thirty-nine".