20138666216 has 16 divisors (see below), whose sum is σ = 37818916740. Its totient is φ = 10053621760.

The previous prime is 20138666203. The next prime is 20138666227. The reversal of 20138666216 is 61266683102.

It can be written as a sum of positive squares in 2 ways, for example, as 20081724100 + 56942116 = 141710^2 + 7546^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1958471 + ... + 1968726.

Almost surely, 2^20138666216 is an apocalyptic number.

It is an amenable number.

20138666216 is a deficient number, since it is larger than the sum of its proper divisors (17680250524).

20138666216 is a wasteful number, since it uses less digits than its factorization.

20138666216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3927844 (or 3927840 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 41.

The spelling of 20138666216 in words is "twenty billion, one hundred thirty-eight million, six hundred sixty-six thousand, two hundred sixteen".