21004112 has 80 divisors (see below), whose sum is σ = 46282752. Its totient is φ = 9185280.

The previous prime is 21004099. The next prime is 21004117. The reversal of 21004112 is 21140012.

It is a junction number, because it is equal to n+sod(n) for n = 21004093 and 21004102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 396278 + ... + 396330.

Almost surely, 2^21004112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21004112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23141376).

21004112 is an abundant number, since it is smaller than the sum of its proper divisors (25278640).

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

21004112 is a wasteful number, since it uses less digits than its factorization.

21004112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21004112 is about 4583.0243289775. The cubic root of 21004112 is about 275.9104239172.

Adding to 21004112 its reverse (21140012), we get a palindrome (42144124).

The spelling of 21004112 in words is "twenty-one million, four thousand, one hundred twelve".