71616221 has 2 divisors, whose sum is σ = 71616222. Its totient is φ = 71616220.

The previous prime is 71616179. The next prime is 71616229. The reversal of 71616221 is 12261617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70644025 + 972196 = 8405^2 + 986^2 .

It is an emirp because it is prime and its reverse (12261617) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71616221 - 2¹⁴ = 71599837 is a prime.

It is a super-2 number, since 2×71616221² = 10257766220641682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71616229) 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 as a sum of consecutive naturals, namely, 35808110 + 35808111.

It is an arithmetic number, because the mean of its divisors is an integer number (35808111).

Almost surely, 2^71616221 is an apocalyptic number.

It is an amenable number.

71616221 is a deficient number, since it is larger than the sum of its proper divisors (1).

71616221 is an equidigital number, since it uses as much as digits as its factorization.

71616221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 26.

The square root of 71616221 is about 8462.6367640352. The cubic root of 71616221 is about 415.2762876895.

Adding to 71616221 its reverse (12261617), we get a palindrome (83877838).

The spelling of 71616221 in words is "seventy-one million, six hundred sixteen thousand, two hundred twenty-one".