81968893 has 8 divisors (see below), whose sum is σ = 83841408. Its totient is φ = 80101824.

The previous prime is 81968839. The next prime is 81968897. The reversal of 81968893 is 39886918.

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

It is a cyclic number.

It is not a de Polignac number, because 81968893 - 2²¹ = 79871741 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81968893.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81968897) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52005 + ... + 53557.

It is an arithmetic number, because the mean of its divisors is an integer number (10480176).

Almost surely, 2^81968893 is an apocalyptic number.

It is an amenable number.

81968893 is a deficient number, since it is larger than the sum of its proper divisors (1872515).

81968893 is a wasteful number, since it uses less digits than its factorization.

81968893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2723.

The product of its digits is 746496, while the sum is 52.

The square root of 81968893 is about 9053.6673784716. The cubic root of 81968893 is about 434.3932051304.

The spelling of 81968893 in words is "eighty-one million, nine hundred sixty-eight thousand, eight hundred ninety-three".