1638468 has 60 divisors (see below), whose sum is σ = 4624620. Its totient is φ = 502848.

The previous prime is 1638463. The next prime is 1638473. The reversal of 1638468 is 8648361.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1638463) and next prime (1638473).

It can be written as a sum of positive squares in 2 ways, for example, as 311364 + 1327104 = 558^2 + 1152^2 .

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

It is not an unprimeable number, because it can be changed into a prime (1638463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4018 + ... + 4406.

It is an arithmetic number, because the mean of its divisors is an integer number (77077).

2^1638468 is an apocalyptic number.

1638468 is a gapful number since it is divisible by the number (18) 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 1638468, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2312310).

1638468 is an abundant number, since it is smaller than the sum of its proper divisors (2986152).

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

1638468 is a wasteful number, since it uses less digits than its factorization.

1638468 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418 (or 407 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 1638468 is about 1280.0265622244. The cubic root of 1638468 is about 117.8906388854.

The spelling of 1638468 in words is "one million, six hundred thirty-eight thousand, four hundred sixty-eight".