11821638 has 16 divisors (see below), whose sum is σ = 23699520. Its totient is φ = 3931176.

The previous prime is 11821631. The next prime is 11821643. The reversal of 11821638 is 83612811.

It is a super-2 number, since 2×11821638² = 279502250006088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11821631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 693 + ... + 4911.

It is an arithmetic number, because the mean of its divisors is an integer number (1481220).

Almost surely, 2^11821638 is an apocalyptic number.

11821638 is an abundant number, since it is smaller than the sum of its proper divisors (11877882).

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

11821638 is a wasteful number, since it uses less digits than its factorization.

11821638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4691.

The product of its digits is 2304, while the sum is 30.

The square root of 11821638 is about 3438.2608976051. The cubic root of 11821638 is about 227.8028844205.

The spelling of 11821638 in words is "eleven million, eight hundred twenty-one thousand, six hundred thirty-eight".