21220024 has 16 divisors (see below), whose sum is σ = 45471600. Its totient is φ = 9094272.

The previous prime is 21220019. The next prime is 21220103. The reversal of 21220024 is 42002212.

It is a junction number, because it is equal to n+sod(n) for n = 21219986 and 21220013.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 189409 + ... + 189520.

It is an arithmetic number, because the mean of its divisors is an integer number (2841975).

Almost surely, 2^21220024 is an apocalyptic number.

It is an amenable number.

21220024 is an abundant number, since it is smaller than the sum of its proper divisors (24251576).

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

21220024 is a wasteful number, since it uses less digits than its factorization.

21220024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378942 (or 378938 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 21220024 is about 4606.5197275166. The cubic root of 21220024 is about 276.8526109248.

Adding to 21220024 its reverse (42002212), we get a palindrome (63222236).

The spelling of 21220024 in words is "twenty-one million, two hundred twenty thousand, twenty-four".