81981068 has 12 divisors (see below), whose sum is σ = 154502880. Its totient is φ = 37837392.

The previous prime is 81981061. The next prime is 81981079. The reversal of 81981068 is 86018918.

It is not an unprimeable number, because it can be changed into a prime (81981061) 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, 788228 + ... + 788331.

It is an arithmetic number, because the mean of its divisors is an integer number (12875240).

Almost surely, 2^81981068 is an apocalyptic number.

It is an amenable number.

81981068 is a deficient number, since it is larger than the sum of its proper divisors (72521812).

81981068 is a wasteful number, since it uses less digits than its factorization.

81981068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1576576 (or 1576574 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 41.

The square root of 81981068 is about 9054.3397329678. The cubic root of 81981068 is about 434.4147111565.

The spelling of 81981068 in words is "eighty-one million, nine hundred eighty-one thousand, sixty-eight".