18400004 has 24 divisors (see below), whose sum is σ = 36935808. Its totient is φ = 7856640.

The previous prime is 18400003. The next prime is 18400013. The reversal of 18400004 is 40000481.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18400003) 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, 7652 + ... + 9764.

It is an arithmetic number, because the mean of its divisors is an integer number (1538992).

Almost surely, 2^18400004 is an apocalyptic number.

18400004 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

18400004 is an abundant number, since it is smaller than the sum of its proper divisors (18535804).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18400004 is a wasteful number, since it uses less digits than its factorization.

18400004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2435 (or 2433 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 18400004 is about 4289.5225841578. The cubic root of 18400004 is about 264.0012434897.

Adding to 18400004 its reverse (40000481), we get a palindrome (58400485).

The spelling of 18400004 in words is "eighteen million, four hundred thousand, four".