81668838 has 8 divisors (see below), whose sum is σ = 163337688. Its totient is φ = 27222944.

The previous prime is 81668827. The next prime is 81668887. The reversal of 81668838 is 83886618.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

81668838 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6805731 + ... + 6805742.

It is an arithmetic number, because the mean of its divisors is an integer number (20417211).

Almost surely, 2^81668838 is an apocalyptic number.

81668838 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81668838 is a wasteful number, since it uses less digits than its factorization.

81668838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13611478.

The product of its digits is 442368, while the sum is 48.

The square root of 81668838 is about 9037.0812766070. The cubic root of 81668838 is about 433.8625110440.

The spelling of 81668838 in words is "eighty-one million, six hundred sixty-eight thousand, eight hundred thirty-eight".