1998006400 has 96 divisors (see below), whose sum is σ = 5315480100. Its totient is φ = 737710080.

The previous prime is 1998006371. The next prime is 1998006407. The reversal of 1998006400 is 46008991.

It can be written as a sum of positive squares in 6 ways, for example, as 366492736 + 1631513664 = 19144^2 + 40392^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1998006400.

It is not an unprimeable number, because it can be changed into a prime (1998006407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17586 + ... + 65614.

Almost surely, 2^1998006400 is an apocalyptic number.

1998006400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998006400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2657740050).

1998006400 is an abundant number, since it is smaller than the sum of its proper divisors (3317473700).

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

1998006400 is a wasteful number, since it uses less digits than its factorization.

1998006400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48066 (or 48049 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 1998006400 is about 44699.0648671759. The cubic root of 1998006400 is about 1259.5022809536.

The spelling of 1998006400 in words is "one billion, nine hundred ninety-eight million, six thousand, four hundred".