71281728 has 224 divisors, whose sum is σ = 245790720. Its totient is φ = 19837440.

The previous prime is 71281687. The next prime is 71281783. The reversal of 71281728 is 82718217.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 71281692 and 71281701.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 858775 + ... + 858857.

It is an arithmetic number, because the mean of its divisors is an integer number (1097280).

Almost surely, 2^71281728 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 71281728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122895360).

71281728 is an abundant number, since it is smaller than the sum of its proper divisors (174508992).

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

71281728 is a wasteful number, since it uses less digits than its factorization.

71281728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 166 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 71281728 is about 8442.8507034058. The cubic root of 71281728 is about 414.6287442818.

The spelling of 71281728 in words is "seventy-one million, two hundred eighty-one thousand, seven hundred twenty-eight".