216381688 has 8 divisors (see below), whose sum is σ = 405715680. Its totient is φ = 108190840.

The previous prime is 216381667. The next prime is 216381703. The reversal of 216381688 is 886183612.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13523848 + ... + 13523863.

It is an arithmetic number, because the mean of its divisors is an integer number (50714460).

Almost surely, 2^216381688 is an apocalyptic number.

It is an amenable number.

216381688 is a deficient number, since it is larger than the sum of its proper divisors (189333992).

216381688 is a wasteful number, since it uses less digits than its factorization.

216381688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27047717 (or 27047713 counting only the distinct ones).

The product of its digits is 110592, while the sum is 43.

The square root of 216381688 is about 14709.9180147273. The cubic root of 216381688 is about 600.3532068489.

The spelling of 216381688 in words is "two hundred sixteen million, three hundred eighty-one thousand, six hundred eighty-eight".