11521638 has 48 divisors (see below), whose sum is σ = 26769600. Its totient is φ = 3570480.

The previous prime is 11521637. The next prime is 11521649. The reversal of 11521638 is 83612511.

11521638 is a `hidden beast` number, since 1 + 1 + 5 + 21 + 638 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11521633) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19893 + ... + 20463.

It is an arithmetic number, because the mean of its divisors is an integer number (557700).

Almost surely, 2^11521638 is an apocalyptic number.

11521638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 11521638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13384800).

11521638 is an abundant number, since it is smaller than the sum of its proper divisors (15247962).

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

11521638 is a wasteful number, since it uses less digits than its factorization.

11521638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657 (or 654 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 11521638 is about 3394.3538413077. The cubic root of 11521638 is about 225.8593507090.

The spelling of 11521638 in words is "eleven million, five hundred twenty-one thousand, six hundred thirty-eight".