1638144 has 90 divisors (see below), whose sum is σ = 4946480. Its totient is φ = 539136.

The previous prime is 1638139. The next prime is 1638149. The reversal of 1638144 is 4418361.

It is an interprime number because it is at equal distance from previous prime (1638139) and next prime (1638149).

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a plaindrome in base 15.

It is a zygodrome in base 2 and base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638149) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 20697 + ... + 20775.

2^1638144 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 1638144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2473240).

1638144 is an abundant number, since it is smaller than the sum of its proper divisors (3308336).

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

1638144 is an frugal number, since it uses more digits than its factorization.

1638144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 84 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 1638144 is about 1279.8999960934. The cubic root of 1638144 is about 117.8828675842.

The spelling of 1638144 in words is "one million, six hundred thirty-eight thousand, one hundred forty-four".