21242120 has 32 divisors (see below), whose sum is σ = 48816000. Its totient is φ = 8315328.

The previous prime is 21242101. The next prime is 21242131. The reversal of 21242120 is 2124212.

It is a junction number, because it is equal to n+sod(n) for n = 21242095 and 21242104.

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, 3770 + ... + 7529.

It is an arithmetic number, because the mean of its divisors is an integer number (1525500).

Almost surely, 2^21242120 is an apocalyptic number.

21242120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21242120 is an abundant number, since it is smaller than the sum of its proper divisors (27573880).

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

21242120 is a wasteful number, since it uses less digits than its factorization.

21242120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11357 (or 11353 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21242120 is about 4608.9174433917. The cubic root of 21242120 is about 276.9486713444.

Adding to 21242120 its reverse (2124212), we get a palindrome (23366332).

The spelling of 21242120 in words is "twenty-one million, two hundred forty-two thousand, one hundred twenty".