1638400002 has 8 divisors (see below), whose sum is σ = 3276800016. Its totient is φ = 546133332.

The previous prime is 1638399989. The next prime is 1638400013. The reversal of 1638400002 is 2000048361.

It is a happy number.

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

1638400002 is an admirable number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136533328 + ... + 136533339.

It is an arithmetic number, because the mean of its divisors is an integer number (409600002).

Almost surely, 2^1638400002 is an apocalyptic number.

1638400002 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1638400002 is a wasteful number, since it uses less digits than its factorization.

1638400002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273066672.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 1638400002 is about 40477.1540748605. The cubic root of 1638400002 is about 1178.8900800446.

Adding to 1638400002 its reverse (2000048361), we get a palindrome (3638448363).

The spelling of 1638400002 in words is "one billion, six hundred thirty-eight million, four hundred thousand, two".