81910080 has 336 divisors, whose sum is σ = 342351360. Its totient is φ = 17547264.

The previous prime is 81910033. The next prime is 81910099. The reversal of 81910080 is 8001918.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×81910080² = 13418522411212800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 342601 + ... + 342839.

Almost surely, 2^81910080 is an apocalyptic number.

81910080 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 81910080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171175680).

81910080 is an abundant number, since it is smaller than the sum of its proper divisors (260441280).

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

81910080 is a wasteful number, since it uses less digits than its factorization.

81910080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286 (or 273 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 81910080 is about 9050.4187748413. The cubic root of 81910080 is about 434.2892873337.

Adding to 81910080 its reverse (8001918), we get a palindrome (89911998).

The spelling of 81910080 in words is "eighty-one million, nine hundred ten thousand, eighty".