81540672 has 56 divisors (see below), whose sum is σ = 216408000. Its totient is φ = 27096576.

The previous prime is 81540631. The next prime is 81540689. The reversal of 81540672 is 27604518.

It is a super-3 number, since 3×81540672³ (a number of 25 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114654 + ... + 115362.

Almost surely, 2^81540672 is an apocalyptic number.

It is an amenable number.

81540672 is an abundant number, since it is smaller than the sum of its proper divisors (134867328).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81540672 is a wasteful number, since it uses less digits than its factorization.

81540672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1323 (or 1313 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 81540672 is about 9029.9873754065. The cubic root of 81540672 is about 433.6354332595.

The spelling of 81540672 in words is "eighty-one million, five hundred forty thousand, six hundred seventy-two".