21123552 has 48 divisors (see below), whose sum is σ = 55883520. Its totient is φ = 6986112.

The previous prime is 21123533. The next prime is 21123589. The reversal of 21123552 is 25532112.

It is a tau number, because it is divible by the number of its divisors (48).

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, 12553 + ... + 14135.

It is an arithmetic number, because the mean of its divisors is an integer number (1164240).

Almost surely, 2^21123552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21123552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27941760).

21123552 is an abundant number, since it is smaller than the sum of its proper divisors (34759968).

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

21123552 is a wasteful number, since it uses less digits than its factorization.

21123552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1735 (or 1727 counting only the distinct ones).

The product of its digits is 600, while the sum is 21.

The square root of 21123552 is about 4596.0365533794. The cubic root of 21123552 is about 276.4324244324.

Adding to 21123552 its reverse (25532112), we get a palindrome (46655664).

The spelling of 21123552 in words is "twenty-one million, one hundred twenty-three thousand, five hundred fifty-two".