81237744 has 120 divisors (see below), whose sum is σ = 263233152. Its totient is φ = 22907520.

The previous prime is 81237677. The next prime is 81237757. The reversal of 81237744 is 44773218.

It is a happy number.

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 81237699 and 81237708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83179 + ... + 84149.

Almost surely, 2^81237744 is an apocalyptic number.

81237744 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81237744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131616576).

81237744 is an abundant number, since it is smaller than the sum of its proper divisors (181995408).

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

81237744 is a wasteful number, since it uses less digits than its factorization.

81237744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1075 (or 1066 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 81237744 is about 9013.1983224602. The cubic root of 81237744 is about 433.0977738800.

The spelling of 81237744 in words is "eighty-one million, two hundred thirty-seven thousand, seven hundred forty-four".