1638009000 has 512 divisors, whose sum is σ = 6230016000. Its totient is φ = 396576000.

The previous prime is 1638008993. The next prime is 1638009013. The reversal of 1638009000 is 9008361.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 15902949 + ... + 15903051.

It is an arithmetic number, because the mean of its divisors is an integer number (12168000).

Almost surely, 2^1638009000 is an apocalyptic number.

1638009000 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 1638009000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3115008000).

1638009000 is an abundant number, since it is smaller than the sum of its proper divisors (4592007000).

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

1638009000 is a wasteful number, since it uses less digits than its factorization.

1638009000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 1638009000 is about 40472.3238769409. The cubic root of 1638009000 is about 1178.7962923958.

The spelling of 1638009000 in words is "one billion, six hundred thirty-eight million, nine thousand".