81540068 has 12 divisors (see below), whose sum is σ = 143003952. Its totient is φ = 40681800.

The previous prime is 81540031. The next prime is 81540079. The reversal of 81540068 is 86004518.

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, 19958 + ... + 23693.

It is an arithmetic number, because the mean of its divisors is an integer number (11916996).

Almost surely, 2^81540068 is an apocalyptic number.

It is an amenable number.

81540068 is a deficient number, since it is larger than the sum of its proper divisors (61463884).

81540068 is a wasteful number, since it uses less digits than its factorization.

81540068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44122 (or 44120 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 81540068 is about 9029.9539312225. The cubic root of 81540068 is about 433.6343625609.

The spelling of 81540068 in words is "eighty-one million, five hundred forty thousand, sixty-eight".