1638044064 has 144 divisors (see below), whose sum is σ = 4792788000. Its totient is φ = 530385408.

The previous prime is 1638044011. The next prime is 1638044071. The reversal of 1638044064 is 4604408361.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4321827 + ... + 4322205.

It is an arithmetic number, because the mean of its divisors is an integer number (33283250).

Almost surely, 2^1638044064 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1638044064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2396394000).

1638044064 is an abundant number, since it is smaller than the sum of its proper divisors (3154743936).

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

1638044064 is a wasteful number, since it uses less digits than its factorization.

1638044064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 787 (or 776 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 1638044064 is about 40472.7570595333. The cubic root of 1638044064 is about 1178.8047036272.

The spelling of 1638044064 in words is "one billion, six hundred thirty-eight million, forty-four thousand, sixty-four".