81271320 has 128 divisors (see below), whose sum is σ = 267321600. Its totient is φ = 19643904.

The previous prime is 81271301. The next prime is 81271327. The reversal of 81271320 is 2317218.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81271327) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 91599 + ... + 92481.

It is an arithmetic number, because the mean of its divisors is an integer number (2088450).

Almost surely, 2^81271320 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 81271320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133660800).

81271320 is an abundant number, since it is smaller than the sum of its proper divisors (186050280).

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

81271320 is a wasteful number, since it uses less digits than its factorization.

81271320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 969 (or 965 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 81271320 is about 9015.0607319086. The cubic root of 81271320 is about 433.1574328809.

Adding to 81271320 its reverse (2317218), we get a palindrome (83588538).

The spelling of 81271320 in words is "eighty-one million, two hundred seventy-one thousand, three hundred twenty".