81251744 has 48 divisors (see below), whose sum is σ = 188729856. Its totient is φ = 33696000.

The previous prime is 81251683. The next prime is 81251783. The reversal of 81251744 is 44715218.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 81251744.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1094 + ... + 12794.

It is an arithmetic number, because the mean of its divisors is an integer number (3931872).

Almost surely, 2^81251744 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 81251744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94364928).

81251744 is an abundant number, since it is smaller than the sum of its proper divisors (107478112).

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

81251744 is a wasteful number, since it uses less digits than its factorization.

81251744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11749 (or 11741 counting only the distinct ones).

The product of its digits is 8960, while the sum is 32.

The square root of 81251744 is about 9013.9749278551. The cubic root of 81251744 is about 433.1226515632.

The spelling of 81251744 in words is "eighty-one million, two hundred fifty-one thousand, seven hundred forty-four".