71563521 has 4 divisors (see below), whose sum is σ = 95418032. Its totient is φ = 47709012.

The previous prime is 71563517. The next prime is 71563529. The reversal of 71563521 is 12536517.

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 not a de Polignac number, because 71563521 - 2² = 71563517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71563529) 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 3 ways as a sum of consecutive naturals, for example, 11927251 + ... + 11927256.

It is an arithmetic number, because the mean of its divisors is an integer number (23854508).

Almost surely, 2^71563521 is an apocalyptic number.

It is an amenable number.

71563521 is a deficient number, since it is larger than the sum of its proper divisors (23854511).

71563521 is a wasteful number, since it uses less digits than its factorization.

71563521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23854510.

The product of its digits is 6300, while the sum is 30.

The square root of 71563521 is about 8459.5225042552. The cubic root of 71563521 is about 415.1744000146.

The spelling of 71563521 in words is "seventy-one million, five hundred sixty-three thousand, five hundred twenty-one".