18147317781 has 4 divisors (see below), whose sum is σ = 24196423712. Its totient is φ = 12098211852.

The previous prime is 18147317779. The next prime is 18147317831. The reversal of 18147317781 is 18771374181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18147317781 - 2¹ = 18147317779 is a prime.

It is a super-2 number, since 2×18147317781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18147317781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18147317711) 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, 3024552961 + ... + 3024552966.

It is an arithmetic number, because the mean of its divisors is an integer number (6049105928).

Almost surely, 2^18147317781 is an apocalyptic number.

It is an amenable number.

18147317781 is a deficient number, since it is larger than the sum of its proper divisors (6049105931).

18147317781 is an equidigital number, since it uses as much as digits as its factorization.

18147317781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6049105930.

The product of its digits is 263424, while the sum is 48.

The spelling of 18147317781 in words is "eighteen billion, one hundred forty-seven million, three hundred seventeen thousand, seven hundred eighty-one".