81185996 has 24 divisors (see below), whose sum is σ = 143663520. Its totient is φ = 40142592.

The previous prime is 81185989. The next prime is 81186013. The reversal of 81185996 is 69958118.

It is a self number, because there is not a number n which added to its sum of digits gives 81185996.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 240740 + ... + 241076.

It is an arithmetic number, because the mean of its divisors is an integer number (5985980).

Almost surely, 2^81185996 is an apocalyptic number.

It is an amenable number.

81185996 is a deficient number, since it is larger than the sum of its proper divisors (62477524).

81185996 is a wasteful number, since it uses less digits than its factorization.

81185996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 833 (or 831 counting only the distinct ones).

The product of its digits is 155520, while the sum is 47.

The square root of 81185996 is about 9010.3271860682. The cubic root of 81185996 is about 433.0057940402.

The spelling of 81185996 in words is "eighty-one million, one hundred eighty-five thousand, nine hundred ninety-six".