81084416 has 90 divisors (see below), whose sum is σ = 190507338. Its totient is φ = 34406400.

The previous prime is 81084413. The next prime is 81084431. The reversal of 81084416 is 61448018.

It can be written as a sum of positive squares in only one way, i.e., 80281600 + 802816 = 8960^2 + 896^2 .

It is a super-2 number, since 2×81084416² = 13149365036122112, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81084413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 802766 + ... + 802866.

Almost surely, 2^81084416 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 81084416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95253669).

81084416 is an abundant number, since it is smaller than the sum of its proper divisors (109422922).

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

81084416 is an equidigital number, since it uses as much as digits as its factorization.

81084416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 32.

The square root of 81084416 is about 9004.6885565243. The cubic root of 81084416 is about 432.8251262400.

The spelling of 81084416 in words is "eighty-one million, eighty-four thousand, four hundred sixteen".