71523521 has 4 divisors (see below), whose sum is σ = 71602944. Its totient is φ = 71444100.

The previous prime is 71523503. The next prime is 71523523. The reversal of 71523521 is 12532517.

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 71523521 - 2⁶ = 71523457 is a prime.

It is a super-2 number, since 2×71523521² = 10231228112474882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71523523) 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, 38345 + ... + 40166.

It is an arithmetic number, because the mean of its divisors is an integer number (17900736).

Almost surely, 2^71523521 is an apocalyptic number.

It is an amenable number.

71523521 is a deficient number, since it is larger than the sum of its proper divisors (79423).

71523521 is an equidigital number, since it uses as much as digits as its factorization.

71523521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79422.

The product of its digits is 2100, while the sum is 26.

The square root of 71523521 is about 8457.1579741660. The cubic root of 71523521 is about 415.0970325195.

The spelling of 71523521 in words is "seventy-one million, five hundred twenty-three thousand, five hundred twenty-one".