16766621138 has 4 divisors (see below), whose sum is σ = 25149931710. Its totient is φ = 8383310568.

The previous prime is 16766621129. The next prime is 16766621141. The reversal of 16766621138 is 83112666761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83112666761 = 23 ⋅3613594207.

It can be written as a sum of positive squares in only one way, i.e., 14252300689 + 2514320449 = 119383^2 + 50143^2 .

It is a super-2 number, since 2×16766621138² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 16766621092 and 16766621101.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4191655283 + ... + 4191655286.

Almost surely, 2^16766621138 is an apocalyptic number.

16766621138 is a deficient number, since it is larger than the sum of its proper divisors (8383310572).

16766621138 is an equidigital number, since it uses as much as digits as its factorization.

16766621138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8383310571.

The product of its digits is 435456, while the sum is 47.

The spelling of 16766621138 in words is "sixteen billion, seven hundred sixty-six million, six hundred twenty-one thousand, one hundred thirty-eight".