21052512 has 72 divisors (see below), whose sum is σ = 64484784. Its totient is φ = 6476544.

The previous prime is 21052489. The next prime is 21052547. The reversal of 21052512 is 21525012.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 933 + ... + 6555.

It is an arithmetic number, because the mean of its divisors is an integer number (895622).

Almost surely, 2^21052512 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 21052512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32242392).

21052512 is an abundant number, since it is smaller than the sum of its proper divisors (43432272).

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

21052512 is a wasteful number, since it uses less digits than its factorization.

21052512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5652 (or 5641 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21052512 is about 4588.3016465790. The cubic root of 21052512 is about 276.1221891234.

Adding to 21052512 its reverse (21525012), we get a palindrome (42577524).

The spelling of 21052512 in words is "twenty-one million, fifty-two thousand, five hundred twelve".