18440666643 has 8 divisors (see below), whose sum is σ = 28100063488. Its totient is φ = 10537523784.

The previous prime is 18440666633. The next prime is 18440666669. The reversal of 18440666643 is 34666604481.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18440666643 - 2⁴ = 18440666627 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18440666592 and 18440666601.

It is not an unprimeable number, because it can be changed into a prime (18440666633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 439063471 + ... + 439063512.

It is an arithmetic number, because the mean of its divisors is an integer number (3512507936).

Almost surely, 2^18440666643 is an apocalyptic number.

18440666643 is a deficient number, since it is larger than the sum of its proper divisors (9659396845).

18440666643 is an equidigital number, since it uses as much as digits as its factorization.

18440666643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878126993.

The product of its (nonzero) digits is 1990656, while the sum is 48.

The spelling of 18440666643 in words is "eighteen billion, four hundred forty million, six hundred sixty-six thousand, six hundred forty-three".