71728721 has 8 divisors (see below), whose sum is σ = 75043584. Its totient is φ = 68488480.

The previous prime is 71728691. The next prime is 71728733. The reversal of 71728721 is 12782717.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 71728721 - 2¹⁴ = 71712337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71728751) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 16685 + ... + 20538.

It is an arithmetic number, because the mean of its divisors is an integer number (9380448).

Almost surely, 2^71728721 is an apocalyptic number.

It is an amenable number.

71728721 is a deficient number, since it is larger than the sum of its proper divisors (3314863).

71728721 is a wasteful number, since it uses less digits than its factorization.

71728721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37311.

The product of its digits is 10976, while the sum is 35.

The square root of 71728721 is about 8469.2810202520. The cubic root of 71728721 is about 415.4936227199.

The spelling of 71728721 in words is "seventy-one million, seven hundred twenty-eight thousand, seven hundred twenty-one".