71705721 has 8 divisors (see below), whose sum is σ = 95716224. Its totient is φ = 47749520.

The previous prime is 71705707. The next prime is 71705731. The reversal of 71705721 is 12750717.

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 71705721 - 2¹⁰ = 71704697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71705701) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 10386 + ... + 15851.

It is an arithmetic number, because the mean of its divisors is an integer number (11964528).

Almost surely, 2^71705721 is an apocalyptic number.

It is an amenable number.

71705721 is a deficient number, since it is larger than the sum of its proper divisors (24010503).

71705721 is a wasteful number, since it uses less digits than its factorization.

71705721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27151.

The product of its (nonzero) digits is 3430, while the sum is 30.

The square root of 71705721 is about 8467.9230629476. The cubic root of 71705721 is about 415.4492082706.

The spelling of 71705721 in words is "seventy-one million, seven hundred five thousand, seven hundred twenty-one".