216128861 has 12 divisors (see below), whose sum is σ = 244212768. Its totient is φ = 190826064.

The previous prime is 216128833. The next prime is 216128873. The reversal of 216128861 is 168821612.

It is a de Polignac number, because none of the positive numbers 2^k-216128861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216128461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23915 + ... + 31688.

It is an arithmetic number, because the mean of its divisors is an integer number (20351064).

Almost surely, 2^216128861 is an apocalyptic number.

It is an amenable number.

216128861 is a deficient number, since it is larger than the sum of its proper divisors (28083907).

216128861 is a wasteful number, since it uses less digits than its factorization.

216128861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55652 (or 55639 counting only the distinct ones).

The product of its digits is 9216, while the sum is 35.

The square root of 216128861 is about 14701.3217432991. The cubic root of 216128861 is about 600.1192920215.

The spelling of 216128861 in words is "two hundred sixteen million, one hundred twenty-eight thousand, eight hundred sixty-one".