81143760 has 80 divisors (see below), whose sum is σ = 252412416. Its totient is φ = 21563904.

The previous prime is 81143759. The next prime is 81143779. The reversal of 81143760 is 6734118.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 133377 + ... + 133983.

Almost surely, 2^81143760 is an apocalyptic number.

81143760 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 81143760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126206208).

81143760 is an abundant number, since it is smaller than the sum of its proper divisors (171268656).

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

81143760 is a wasteful number, since it uses less digits than its factorization.

81143760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1180 (or 1174 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 81143760 is about 9007.9831260943. The cubic root of 81143760 is about 432.9306923971.

Adding to 81143760 its reverse (6734118), we get a palindrome (87877878).

The spelling of 81143760 in words is "eighty-one million, one hundred forty-three thousand, seven hundred sixty".