71216209 has 4 divisors (see below), whose sum is σ = 72117760. Its totient is φ = 70314660.

The previous prime is 71216183. The next prime is 71216239. The reversal of 71216209 is 90261217.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90261217 = 137 ⋅658841.

It is a cyclic number.

It is not a de Polignac number, because 71216209 - 2¹⁹ = 70691921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71216239) 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 3 ways as a sum of consecutive naturals, for example, 450657 + ... + 450814.

It is an arithmetic number, because the mean of its divisors is an integer number (18029440).

Almost surely, 2^71216209 is an apocalyptic number.

71216209 is a gapful number since it is divisible by the number (79) formed by its first and last digit.

It is an amenable number.

71216209 is a deficient number, since it is larger than the sum of its proper divisors (901551).

71216209 is an equidigital number, since it uses as much as digits as its factorization.

71216209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901550.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 71216209 is about 8438.9696645977. The cubic root of 71216209 is about 414.5016692282.

The spelling of 71216209 in words is "seventy-one million, two hundred sixteen thousand, two hundred nine".