18639648 has 72 divisors (see below), whose sum is σ = 53926236. Its totient is φ = 6105600.

The previous prime is 18639631. The next prime is 18639653. The reversal of 18639648 is 84693681.

18639648 is a `hidden beast` number, since 1 + 8 + 639 + 6 + 4 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17740944 + 898704 = 4212^2 + 948^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17038 + ... + 18098.

Almost surely, 2^18639648 is an apocalyptic number.

18639648 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 18639648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26963118).

18639648 is an abundant number, since it is smaller than the sum of its proper divisors (35286588).

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

18639648 is a wasteful number, since it uses less digits than its factorization.

18639648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138 (or 1127 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 18639648 is about 4317.3658635793. The cubic root of 18639648 is about 265.1424320353.

It can be divided in two parts, 1863 and 9648, that added together give a palindrome (11511).

The spelling of 18639648 in words is "eighteen million, six hundred thirty-nine thousand, six hundred forty-eight".