21264552 has 64 divisors (see below), whose sum is σ = 62553600. Its totient is φ = 6670080.

The previous prime is 21264541. The next prime is 21264559. The reversal of 21264552 is 25546212.

21264552 is a `hidden beast` number, since 2 + 12 + 645 + 5 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21264559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 777 + ... + 6567.

It is an arithmetic number, because the mean of its divisors is an integer number (977400).

Almost surely, 2^21264552 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 21264552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31276800).

21264552 is an abundant number, since it is smaller than the sum of its proper divisors (41289048).

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

21264552 is a wasteful number, since it uses less digits than its factorization.

21264552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5823 (or 5813 counting only the distinct ones).

The product of its digits is 4800, while the sum is 27.

The square root of 21264552 is about 4611.3503445303. The cubic root of 21264552 is about 277.0461243771.

The spelling of 21264552 in words is "twenty-one million, two hundred sixty-four thousand, five hundred fifty-two".