81113724 has 60 divisors (see below), whose sum is σ = 214799200. Its totient is φ = 26687232.

The previous prime is 81113723. The next prime is 81113761. The reversal of 81113724 is 42731118.

It is a super-3 number, since 3×81113724³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81113723) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 24012 + ... + 27180.

Almost surely, 2^81113724 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81113724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107399600).

81113724 is an abundant number, since it is smaller than the sum of its proper divisors (133685476).

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

81113724 is a wasteful number, since it uses less digits than its factorization.

81113724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3264 (or 3253 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 81113724 is about 9006.3157839374. The cubic root of 81113724 is about 432.8772682396.

It can be divided in two parts, 811 and 13724, that added together give a triangular number (14535 = T₁₇₀).

The spelling of 81113724 in words is "eighty-one million, one hundred thirteen thousand, seven hundred twenty-four".