21120252 has 12 divisors (see below), whose sum is σ = 49280616. Its totient is φ = 7040080.

The previous prime is 21120251. The next prime is 21120257. The reversal of 21120252 is 25202112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 879999 + ... + 880022.

It is an arithmetic number, because the mean of its divisors is an integer number (4106718).

Almost surely, 2^21120252 is an apocalyptic number.

It is an amenable number.

21120252 is an abundant number, since it is smaller than the sum of its proper divisors (28160364).

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

21120252 is a wasteful number, since it uses less digits than its factorization.

21120252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760028 (or 1760026 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21120252 is about 4595.6775343795. The cubic root of 21120252 is about 276.4180285816.

Adding to 21120252 its reverse (25202112), we get a palindrome (46322364).

The spelling of 21120252 in words is "twenty-one million, one hundred twenty thousand, two hundred fifty-two".