71291521 has 8 divisors (see below), whose sum is σ = 83139200. Its totient is φ = 61106724.

The previous prime is 71291509. The next prime is 71291531. The reversal of 71291521 is 12519217.

It is not a de Polignac number, because 71291521 - 2⁹ = 71291009 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 71291521.

It is not an unprimeable number, because it can be changed into a prime (71291501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 103581 + ... + 104266.

It is an arithmetic number, because the mean of its divisors is an integer number (10392400).

Almost surely, 2^71291521 is an apocalyptic number.

It is an amenable number.

71291521 is a deficient number, since it is larger than the sum of its proper divisors (11847679).

71291521 is an equidigital number, since it uses as much as digits as its factorization.

71291521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207868 (or 207854 counting only the distinct ones).

The product of its digits is 1260, while the sum is 28.

The square root of 71291521 is about 8443.4306416290. The cubic root of 71291521 is about 414.6477312577.

The spelling of 71291521 in words is "seventy-one million, two hundred ninety-one thousand, five hundred twenty-one".