21212124 has 24 divisors (see below), whose sum is σ = 52406928. Its totient is φ = 6654720.

The previous prime is 21212119. The next prime is 21212131. The reversal of 21212124 is 42121212.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51787 + ... + 52194.

It is an arithmetic number, because the mean of its divisors is an integer number (2183622).

Almost surely, 2^21212124 is an apocalyptic number.

It is an amenable number.

21212124 is an abundant number, since it is smaller than the sum of its proper divisors (31194804).

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

21212124 is a wasteful number, since it uses less digits than its factorization.

21212124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104005 (or 104003 counting only the distinct ones).

The product of its digits is 64, while the sum is 15.

The square root of 21212124 is about 4605.6621673762. The cubic root of 21212124 is about 276.8182501861.

Adding to 21212124 its reverse (42121212), we get a palindrome (63333336).

It can be divided in two parts, 2121212 and 4, that multiplied together give a palindrome (8484848).

The spelling of 21212124 in words is "twenty-one million, two hundred twelve thousand, one hundred twenty-four".