18644440851 has 12 divisors (see below), whose sum is σ = 26937638728. Its totient is φ = 12426498144.

The previous prime is 18644440817. The next prime is 18644440853. The reversal of 18644440851 is 15804444681.

It is not a de Polignac number, because 18644440851 - 2¹¹ = 18644438803 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18644440797 and 18644440806.

It is not an unprimeable number, because it can be changed into a prime (18644440853) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 222730 + ... + 294783.

Almost surely, 2^18644440851 is an apocalyptic number.

18644440851 is a deficient number, since it is larger than the sum of its proper divisors (8293197877).

18644440851 is a wasteful number, since it uses less digits than its factorization.

18644440851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521522 (or 521519 counting only the distinct ones).

The product of its (nonzero) digits is 491520, while the sum is 45.

The spelling of 18644440851 in words is "eighteen billion, six hundred forty-four million, four hundred forty thousand, eight hundred fifty-one".