81169280 has 32 divisors (see below), whose sum is σ = 194046840. Its totient is φ = 32467456.

The previous prime is 81169267. The next prime is 81169307. The reversal of 81169280 is 8296118.

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 81169280.

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 3 ways as a sum of consecutive naturals, for example, 62774 + ... + 64053.

Almost surely, 2^81169280 is an apocalyptic number.

81169280 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81169280 is an abundant number, since it is smaller than the sum of its proper divisors (112877560).

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

81169280 is a wasteful number, since it uses less digits than its factorization.

81169280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126846 (or 126834 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 81169280 is about 9009.3995360401. The cubic root of 81169280 is about 432.9760737188.

The spelling of 81169280 in words is "eighty-one million, one hundred sixty-nine thousand, two hundred eighty".