18000405 has 12 divisors (see below), whose sum is σ = 31200780. Its totient is φ = 9600192.

The previous prime is 18000403. The next prime is 18000407. The reversal of 18000405 is 50400081.

It is an interprime number because it is at equal distance from previous prime (18000403) and next prime (18000407).

It can be written as a sum of positive squares in 2 ways, for example, as 12552849 + 5447556 = 3543^2 + 2334^2 .

It is not a de Polignac number, because 18000405 - 2¹ = 18000403 is a prime.

18000405 is a modest number, since divided by 405 gives 180 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18000401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 199960 + ... + 200049.

It is an arithmetic number, because the mean of its divisors is an integer number (2600065).

Almost surely, 2^18000405 is an apocalyptic number.

18000405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18000405 is a deficient number, since it is larger than the sum of its proper divisors (13200375).

18000405 is a wasteful number, since it uses less digits than its factorization.

18000405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400020 (or 400017 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 18000405 is about 4242.6884165585. The cubic root of 18000405 is about 262.0761049622.

Adding to 18000405 its reverse (50400081), we get a palindrome (68400486).

It can be divided in two parts, 18000 and 405, that multiplied together give a square (7290000 = 2700²).

The spelling of 18000405 in words is "eighteen million, four hundred five", and thus it is an aban number.