18548017591993 has 4 divisors (see below), whose sum is σ = 19187604405540. Its totient is φ = 17908430778448.

The previous prime is 18548017591963. The next prime is 18548017592023. The reversal of 18548017591993 is 39919571084581.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (18548017591963) and next prime (18548017592023).

It can be written as a sum of positive squares in 2 ways, for example, as 3509226663849 + 15038790928144 = 1873293^2 + 3877988^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18548017591993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18548017591963) 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, 319793406730 + ... + 319793406787.

It is an arithmetic number, because the mean of its divisors is an integer number (4796901101385).

Almost surely, 2^{18548017591993} is an apocalyptic number.

It is an amenable number.

18548017591993 is a deficient number, since it is larger than the sum of its proper divisors (639586813547).

18548017591993 is an equidigital number, since it uses as much as digits as its factorization.

18548017591993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639586813546.

The product of its (nonzero) digits is 97977600, while the sum is 70.

The spelling of 18548017591993 in words is "eighteen trillion, five hundred forty-eight billion, seventeen million, five hundred ninety-one thousand, nine hundred ninety-three".