18038861993 has 8 divisors (see below), whose sum is σ = 19101151368. Its totient is φ = 16976703744.

The previous prime is 18038861987. The next prime is 18038861999. The reversal of 18038861993 is 39916883081.

It is an interprime number because it is at equal distance from previous prime (18038861987) and next prime (18038861999).

It can be written as a sum of positive squares in 4 ways, for example, as 2510711449 + 15528150544 = 50107^2 + 124612^2 .

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

It is not a de Polignac number, because 18038861993 - 2¹² = 18038857897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18038861999) 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, 477755 + ... + 514127.

It is an arithmetic number, because the mean of its divisors is an integer number (2387643921).

Almost surely, 2^18038861993 is an apocalyptic number.

It is an amenable number.

18038861993 is a deficient number, since it is larger than the sum of its proper divisors (1062289375).

18038861993 is a wasteful number, since it uses less digits than its factorization.

18038861993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65563.

The product of its (nonzero) digits is 2239488, while the sum is 56.

The spelling of 18038861993 in words is "eighteen billion, thirty-eight million, eight hundred sixty-one thousand, nine hundred ninety-three".