216686128 has 40 divisors (see below), whose sum is σ = 442257408. Its totient is φ = 102645312.

The previous prime is 216686111. The next prime is 216686137. The reversal of 216686128 is 821686612.

216686128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36625 + ... + 42127.

Almost surely, 2^216686128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216686128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221128704).

216686128 is an abundant number, since it is smaller than the sum of its proper divisors (225571280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216686128 is a wasteful number, since it uses less digits than its factorization.

216686128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5641 (or 5635 counting only the distinct ones).

The product of its digits is 55296, while the sum is 40.

The square root of 216686128 is about 14720.2624976595. The cubic root of 216686128 is about 600.6346322036.

The spelling of 216686128 in words is "two hundred sixteen million, six hundred eighty-six thousand, one hundred twenty-eight".