21111008 has 48 divisors (see below), whose sum is σ = 44470944. Its totient is φ = 9830400.

The previous prime is 21111007. The next prime is 21111029. The reversal of 21111008 is 80011112.

It is a junction number, because it is equal to n+sod(n) for n = 21110983 and 21111001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82016 + ... + 82272.

It is an arithmetic number, because the mean of its divisors is an integer number (926478).

Almost surely, 2^21111008 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 21111008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22235472).

21111008 is an abundant number, since it is smaller than the sum of its proper divisors (23359936).

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

21111008 is a wasteful number, since it uses less digits than its factorization.

21111008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435 (or 427 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

The square root of 21111008 is about 4594.6716966504. The cubic root of 21111008 is about 276.3776947646.

The spelling of 21111008 in words is "twenty-one million, one hundred eleven thousand, eight".