1638240 has 48 divisors (see below), whose sum is σ = 5161968. Its totient is φ = 436736.

The previous prime is 1638211. The next prime is 1638251. The reversal of 1638240 is 428361.

It is a happy number.

1638240 is nontrivially palindromic in base 11.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1638240.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1227 + ... + 2186.

It is an arithmetic number, because the mean of its divisors is an integer number (107541).

2^1638240 is an apocalyptic number.

1638240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638240 is an abundant number, since it is smaller than the sum of its proper divisors (3523728).

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

1638240 is a wasteful number, since it uses less digits than its factorization.

1638240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3431 (or 3423 counting only the distinct ones).

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

The square root of 1638240 is about 1279.9374984740. The cubic root of 1638240 is about 117.8851702988.

The spelling of 1638240 in words is "one million, six hundred thirty-eight thousand, two hundred forty".