21008124 has 36 divisors (see below), whose sum is σ = 56229264. Its totient is φ = 6590592.

The previous prime is 21008083. The next prime is 21008149. The reversal of 21008124 is 42180012.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21008097 and 21008106.

It is a congruent number.

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, 16552 + ... + 17775.

It is an arithmetic number, because the mean of its divisors is an integer number (1561924).

Almost surely, 2^21008124 is an apocalyptic number.

It is an amenable number.

21008124 is an abundant number, since it is smaller than the sum of its proper divisors (35221140).

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

21008124 is a wasteful number, since it uses less digits than its factorization.

21008124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34354 (or 34349 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 21008124 is about 4583.4620103149. The cubic root of 21008124 is about 275.9279900355.

Adding to 21008124 its reverse (42180012), we get a palindrome (63188136).

The spelling of 21008124 in words is "twenty-one million, eight thousand, one hundred twenty-four".