81345744 has 60 divisors (see below), whose sum is σ = 228986212. Its totient is φ = 26956800.

The previous prime is 81345743. The next prime is 81345749. The reversal of 81345744 is 44754318.

81345744 is a `hidden beast` number, since 81 + 3 + 4 + 574 + 4 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 345744 + 81000000 = 588^2 + 9000^2 .

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 = 81345699 and 81345708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81345743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24504 + ... + 27624.

Almost surely, 2^81345744 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 81345744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114493106).

81345744 is an abundant number, since it is smaller than the sum of its proper divisors (147640468).

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

81345744 is a wasteful number, since it uses less digits than its factorization.

81345744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3316 (or 3307 counting only the distinct ones).

The product of its digits is 53760, while the sum is 36.

The square root of 81345744 is about 9019.1875465587. The cubic root of 81345744 is about 433.2896134721.

It can be divided in two parts, 81 and 345744, that multiplied together give a square (28005264 = 5292²).

The spelling of 81345744 in words is "eighty-one million, three hundred forty-five thousand, seven hundred forty-four".