216640028756 has 6 divisors (see below), whose sum is σ = 379120050330. Its totient is φ = 108320014376.

The previous prime is 216640028743. The next prime is 216640028797. The reversal of 216640028756 is 657820046612.

It can be written as a sum of positive squares in only one way, i.e., 211057548100 + 5582480656 = 459410^2 + 74716^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 216640028756.

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, 27080003591 + ... + 27080003598.

It is an arithmetic number, because the mean of its divisors is an integer number (63186675055).

Almost surely, 2^216640028756 is an apocalyptic number.

It is an amenable number.

216640028756 is a deficient number, since it is larger than the sum of its proper divisors (162480021574).

216640028756 is a wasteful number, since it uses less digits than its factorization.

216640028756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54160007193 (or 54160007191 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 47.

The spelling of 216640028756 in words is "two hundred sixteen billion, six hundred forty million, twenty-eight thousand, seven hundred fifty-six".