216661671 has 24 divisors (see below), whose sum is σ = 322148736. Its totient is φ = 140232960.

The previous prime is 216661667. The next prime is 216661699. The reversal of 216661671 is 176166612.

It is not a de Polignac number, because 216661671 - 2² = 216661667 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216661661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80971 + ... + 83603.

It is an arithmetic number, because the mean of its divisors is an integer number (13422864).

Almost surely, 2^216661671 is an apocalyptic number.

216661671 is a deficient number, since it is larger than the sum of its proper divisors (105487065).

216661671 is a wasteful number, since it uses less digits than its factorization.

216661671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2903 (or 2900 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 216661671 is about 14719.4317485425. The cubic root of 216661671 is about 600.6120338121.

The spelling of 216661671 in words is "two hundred sixteen million, six hundred sixty-one thousand, six hundred seventy-one".