18638147491 has 8 divisors (see below), whose sum is σ = 18748497600. Its totient is φ = 18527866920.

The previous prime is 18638147441. The next prime is 18638147501. The reversal of 18638147491 is 19474183681.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18638147491 - 2¹⁵ = 18638114723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18638147441) 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, 580620 + ... + 611878.

It is an arithmetic number, because the mean of its divisors is an integer number (2343562200).

Almost surely, 2^18638147491 is an apocalyptic number.

18638147491 is a deficient number, since it is larger than the sum of its proper divisors (110350109).

18638147491 is a wasteful number, since it uses less digits than its factorization.

18638147491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34769.

The product of its digits is 1161216, while the sum is 52.

The spelling of 18638147491 in words is "eighteen billion, six hundred thirty-eight million, one hundred forty-seven thousand, four hundred ninety-one".