81332872 has 8 divisors (see below), whose sum is σ = 152499150. Its totient is φ = 40666432.

The previous prime is 81332861. The next prime is 81332873. The reversal of 81332872 is 27823318.

It can be written as a sum of positive squares in only one way, i.e., 72488196 + 8844676 = 8514^2 + 2974^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (81332873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5083297 + ... + 5083312.

Almost surely, 2^81332872 is an apocalyptic number.

It is an amenable number.

81332872 is a deficient number, since it is larger than the sum of its proper divisors (71166278).

81332872 is a wasteful number, since it uses less digits than its factorization.

81332872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10166615 (or 10166611 counting only the distinct ones).

The product of its digits is 16128, while the sum is 34.

The square root of 81332872 is about 9018.4739285535. The cubic root of 81332872 is about 433.2667579510.

The spelling of 81332872 in words is "eighty-one million, three hundred thirty-two thousand, eight hundred seventy-two".