18821947005 has 24 divisors (see below), whose sum is σ = 32633605368. Its totient is φ = 10035634176.

The previous prime is 18821947003. The next prime is 18821947007. The reversal of 18821947005 is 50074912881.

It is an interprime number because it is at equal distance from previous prime (18821947003) and next prime (18821947007).

It can be written as a sum of positive squares in 4 ways, for example, as 4656424644 + 14165522361 = 68238^2 + 119019^2 .

It is not a de Polignac number, because 18821947005 - 2¹ = 18821947003 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18821947003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 115549 + ... + 225821.

It is an arithmetic number, because the mean of its divisors is an integer number (1359733557).

Almost surely, 2^18821947005 is an apocalyptic number.

18821947005 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18821947005 is a deficient number, since it is larger than the sum of its proper divisors (13811658363).

18821947005 is a wasteful number, since it uses less digits than its factorization.

18821947005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114077 (or 114074 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 18821947005 in words is "eighteen billion, eight hundred twenty-one million, nine hundred forty-seven thousand, five".