81539272 has 16 divisors (see below), whose sum is σ = 153120240. Its totient is φ = 40707216.

The previous prime is 81539251. The next prime is 81539273. The reversal of 81539272 is 27293518.

It is not an unprimeable number, because it can be changed into a prime (81539273) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1998 + ... + 12925.

It is an arithmetic number, because the mean of its divisors is an integer number (9570015).

Almost surely, 2^81539272 is an apocalyptic number.

It is an amenable number.

81539272 is a deficient number, since it is larger than the sum of its proper divisors (71580968).

81539272 is a wasteful number, since it uses less digits than its factorization.

81539272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15612 (or 15608 counting only the distinct ones).

The product of its digits is 30240, while the sum is 37.

The square root of 81539272 is about 9029.9098555855. The cubic root of 81539272 is about 433.6329514997.

The spelling of 81539272 in words is "eighty-one million, five hundred thirty-nine thousand, two hundred seventy-two".