81000068 has 12 divisors (see below), whose sum is σ = 142654092. Its totient is φ = 40241760.

The previous prime is 81000061. The next prime is 81000071. The reversal of 81000068 is 86000018.

It can be written as a sum of positive squares in 2 ways, for example, as 60497284 + 20502784 = 7778^2 + 4528^2 .

It is a super-2 number, since 2×81000068² = 13122022032009248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81000061) 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, 63863 + ... + 65118.

It is an arithmetic number, because the mean of its divisors is an integer number (11887841).

Almost surely, 2^81000068 is an apocalyptic number.

It is an amenable number.

81000068 is a deficient number, since it is larger than the sum of its proper divisors (61654024).

81000068 is a wasteful number, since it uses less digits than its factorization.

81000068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129142 (or 129140 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 81000068 is about 9000.0037777770. The cubic root of 81000068 is about 432.6749921699.

The spelling of 81000068 in words is "eighty-one million, sixty-eight", and thus it is an aban number and an uban number.