81747144 has 112 divisors (see below), whose sum is σ = 233727120. Its totient is φ = 26788320.

The previous prime is 81747131. The next prime is 81747157. The reversal of 81747144 is 44174718.

It is an interprime number because it is at equal distance from previous prime (81747131) and next prime (81747157).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81747099 and 81747108.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 623959 + ... + 624089.

Almost surely, 2^81747144 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 81747144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116863560).

81747144 is an abundant number, since it is smaller than the sum of its proper divisors (151979976).

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

81747144 is a wasteful number, since it uses less digits than its factorization.

81747144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262 (or 243 counting only the distinct ones).

The product of its digits is 25088, while the sum is 36.

The square root of 81747144 is about 9041.4127214722. The cubic root of 81747144 is about 434.0011326041.

It can be divided in two parts, 8174714 and 4, that added together give a palindrome (8174718).

The spelling of 81747144 in words is "eighty-one million, seven hundred forty-seven thousand, one hundred forty-four".