216661887 has 36 divisors (see below), whose sum is σ = 341186664. Its totient is φ = 132425280.

The previous prime is 216661877. The next prime is 216661931. The reversal of 216661887 is 788166612.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-216661887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216661877) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 274908 + ... + 275694.

Almost surely, 2^216661887 is an apocalyptic number.

216661887 is a deficient number, since it is larger than the sum of its proper divisors (124524777).

216661887 is a wasteful number, since it uses less digits than its factorization.

216661887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000 (or 984 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 216661887 is about 14719.4390857804. The cubic root of 216661887 is about 600.6122334046.

The spelling of 216661887 in words is "two hundred sixteen million, six hundred sixty-one thousand, eight hundred eighty-seven".