81278080 has 64 divisors (see below), whose sum is σ = 209273400. Its totient is φ = 30007296.

The previous prime is 81278069. The next prime is 81278083. The reversal of 81278080 is 8087218.

It can be written as a sum of positive squares in 4 ways, for example, as 44408896 + 36869184 = 6664^2 + 6072^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×81278080² = 13212252576972800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81278083) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3436 + ... + 13204.

Almost surely, 2^81278080 is an apocalyptic number.

81278080 is a gapful number since it is divisible by the number (80) 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 81278080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104636700).

81278080 is an abundant number, since it is smaller than the sum of its proper divisors (127995320).

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

81278080 is a wasteful number, since it uses less digits than its factorization.

81278080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9801 (or 9789 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 34.

The square root of 81278080 is about 9015.4356522577. The cubic root of 81278080 is about 433.1694422961.

The spelling of 81278080 in words is "eighty-one million, two hundred seventy-eight thousand, eighty".