216581671 has 2 divisors, whose sum is σ = 216581672. Its totient is φ = 216581670.

The previous prime is 216581653. The next prime is 216581681. The reversal of 216581671 is 176185612.

216581671 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 216581671 - 2⁷ = 216581543 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216581671.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216581621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108290835 + 108290836.

It is an arithmetic number, because the mean of its divisors is an integer number (108290836).

Almost surely, 2^216581671 is an apocalyptic number.

216581671 is a deficient number, since it is larger than the sum of its proper divisors (1).

216581671 is an equidigital number, since it uses as much as digits as its factorization.

216581671 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 37.

The square root of 216581671 is about 14716.7140014339. The cubic root of 216581671 is about 600.5381015262.

The spelling of 216581671 in words is "two hundred sixteen million, five hundred eighty-one thousand, six hundred seventy-one".