71057521 has 4 divisors (see below), whose sum is σ = 71078512. Its totient is φ = 71036532.

The previous prime is 71057513. The next prime is 71057531. The reversal of 71057521 is 12575017.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 71057521 - 2³ = 71057513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71057521.

It is not an unprimeable number, because it can be changed into a prime (71057531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4131 + ... + 12616.

It is an arithmetic number, because the mean of its divisors is an integer number (17769628).

Almost surely, 2^71057521 is an apocalyptic number.

It is an amenable number.

71057521 is a deficient number, since it is larger than the sum of its proper divisors (20991).

71057521 is a wasteful number, since it uses less digits than its factorization.

71057521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20990.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 71057521 is about 8429.5623255303. The cubic root of 71057521 is about 414.1935682215.

The spelling of 71057521 in words is "seventy-one million, fifty-seven thousand, five hundred twenty-one".