28666816638 has 16 divisors (see below), whose sum is σ = 57336458256. Its totient is φ = 9555134720.

The previous prime is 28666816603. The next prime is 28666816667. The reversal of 28666816638 is 83661866682.

It is a happy number.

It is a Curzon number.

It is a congruent number.

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, 28108 + ... + 241088.

It is an arithmetic number, because the mean of its divisors is an integer number (3583528641).

Almost surely, 2^28666816638 is an apocalyptic number.

28666816638 is an abundant number, since it is smaller than the sum of its proper divisors (28669641618).

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

28666816638 is a wasteful number, since it uses less digits than its factorization.

28666816638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235419.

The product of its digits is 23887872, while the sum is 60.

The spelling of 28666816638 in words is "twenty-eight billion, six hundred sixty-six million, eight hundred sixteen thousand, six hundred thirty-eight".