71515728 has 60 divisors (see below), whose sum is σ = 201240468. Its totient is φ = 23708160.

The previous prime is 71515687. The next prime is 71515739. The reversal of 71515728 is 82751517.

71515728 is a `hidden beast` number, since 71 + 515 + 72 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 31674384 + 39841344 = 5628^2 + 6312^2 .

It is a super-2 number, since 2×71515728² = 10228998702739968, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 71515692 and 71515701.

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 11 ways as a sum of consecutive naturals, for example, 27108 + ... + 29628.

Almost surely, 2^71515728 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 71515728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100620234).

71515728 is an abundant number, since it is smaller than the sum of its proper divisors (129724740).

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

71515728 is a wasteful number, since it uses less digits than its factorization.

71515728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2732 (or 2723 counting only the distinct ones).

The product of its digits is 19600, while the sum is 36.

The square root of 71515728 is about 8456.6972276415. The cubic root of 71515728 is about 415.0819560401.

The spelling of 71515728 in words is "seventy-one million, five hundred fifteen thousand, seven hundred twenty-eight".