81668383 has 4 divisors (see below), whose sum is σ = 82702240. Its totient is φ = 80634528.

The previous prime is 81668381. The next prime is 81668387. The reversal of 81668383 is 38386618.

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 81668383 - 2¹ = 81668381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81668381) 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, 516810 + ... + 516967.

It is an arithmetic number, because the mean of its divisors is an integer number (20675560).

Almost surely, 2^81668383 is an apocalyptic number.

81668383 is a deficient number, since it is larger than the sum of its proper divisors (1033857).

81668383 is a wasteful number, since it uses less digits than its factorization.

81668383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1033856.

The product of its digits is 165888, while the sum is 43.

The square root of 81668383 is about 9037.0561025148. The cubic root of 81668383 is about 433.8617053193.

The spelling of 81668383 in words is "eighty-one million, six hundred sixty-eight thousand, three hundred eighty-three".