81129732 has 24 divisors (see below), whose sum is σ = 189506016. Its totient is φ = 27014208.

The previous prime is 81129731. The next prime is 81129751. The reversal of 81129732 is 23792118.

It is a super-3 number, since 3×81129732³ (a number of 25 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81129693 and 81129702.

It is not an unprimeable number, because it can be changed into a prime (81129731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10083 + ... + 16245.

It is an arithmetic number, because the mean of its divisors is an integer number (7896084).

Almost surely, 2^81129732 is an apocalyptic number.

It is an amenable number.

81129732 is an abundant number, since it is smaller than the sum of its proper divisors (108376284).

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

81129732 is a wasteful number, since it uses less digits than its factorization.

81129732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7267 (or 7265 counting only the distinct ones).

The product of its digits is 6048, while the sum is 33.

The square root of 81129732 is about 9007.2044497724. The cubic root of 81129732 is about 432.9057428436.

The spelling of 81129732 in words is "eighty-one million, one hundred twenty-nine thousand, seven hundred thirty-two".