18916868647 has 4 divisors (see below), whose sum is σ = 18917143776. Its totient is φ = 18916593520.

The previous prime is 18916868623. The next prime is 18916868669. The reversal of 18916868647 is 74686861981.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 18916868647 - 2¹¹ = 18916866599 is a prime.

It is a super-2 number, since 2×18916868647² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18916868617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64818 + ... + 205024.

It is an arithmetic number, because the mean of its divisors is an integer number (4729285944).

Almost surely, 2^18916868647 is an apocalyptic number.

18916868647 is a deficient number, since it is larger than the sum of its proper divisors (275129).

18916868647 is a wasteful number, since it uses less digits than its factorization.

18916868647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275128.

The product of its digits is 27869184, while the sum is 64.

The spelling of 18916868647 in words is "eighteen billion, nine hundred sixteen million, eight hundred sixty-eight thousand, six hundred forty-seven".