18661416681 has 16 divisors (see below), whose sum is σ = 27057573504. Its totient is φ = 11392660224.

The previous prime is 18661416667. The next prime is 18661416701.

18661416681 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 18661416681 - 2⁶ = 18661416617 is a prime.

It is a super-2 number, since 2×18661416681² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18661416681.

It is not an unprimeable number, because it can be changed into a prime (18661416281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4942845 + ... + 4946618.

It is an arithmetic number, because the mean of its divisors is an integer number (1691098344).

Almost surely, 2^18661416681 is an apocalyptic number.

It is an amenable number.

18661416681 is a deficient number, since it is larger than the sum of its proper divisors (8396156823).

18661416681 is a wasteful number, since it uses less digits than its factorization.

18661416681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9889520.

The product of its digits is 331776, while the sum is 48.

The spelling of 18661416681 in words is "eighteen billion, six hundred sixty-one million, four hundred sixteen thousand, six hundred eighty-one".