81351450 has 72 divisors (see below), whose sum is σ = 219665628. Its totient is φ = 21584640.

The previous prime is 81351379. The next prime is 81351451. The reversal of 81351450 is 5415318.

It can be written as a sum of positive squares in 6 ways, for example, as 26842761 + 54508689 = 5181^2 + 7383^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81351451) 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 35 ways as a sum of consecutive naturals, for example, 131542 + ... + 132158.

Almost surely, 2^81351450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81351450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109832814).

81351450 is an abundant number, since it is smaller than the sum of its proper divisors (138314178).

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

81351450 is a wasteful number, since it uses less digits than its factorization.

81351450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 928 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 81351450 is about 9019.5038666215. The cubic root of 81351450 is about 433.2997442735.

Adding to 81351450 its reverse (5415318), we get a palindrome (86766768).

The spelling of 81351450 in words is "eighty-one million, three hundred fifty-one thousand, four hundred fifty".