71271521 has 4 divisors (see below), whose sum is σ = 71387652. Its totient is φ = 71155392.

The previous prime is 71271493. The next prime is 71271533. The reversal of 71271521 is 12517217.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27447121 + 43824400 = 5239^2 + 6620^2 .

It is a cyclic number.

It is not a de Polignac number, because 71271521 - 2¹⁰ = 71270497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71271581) 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, 57140 + ... + 58373.

It is an arithmetic number, because the mean of its divisors is an integer number (17846913).

Almost surely, 2^71271521 is an apocalyptic number.

It is an amenable number.

71271521 is a deficient number, since it is larger than the sum of its proper divisors (116131).

71271521 is a wasteful number, since it uses less digits than its factorization.

71271521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116130.

The product of its digits is 980, while the sum is 26.

The square root of 71271521 is about 8442.2462058388. The cubic root of 71271521 is about 414.6089527788.

Adding to 71271521 its reverse (12517217), we get a palindrome (83788738).

The spelling of 71271521 in words is "seventy-one million, two hundred seventy-one thousand, five hundred twenty-one".