21321053 has 8 divisors (see below), whose sum is σ = 23027928. Its totient is φ = 19623744.

The previous prime is 21321031. The next prime is 21321067. The reversal of 21321053 is 35012312.

It can be written as a sum of positive squares in 4 ways, for example, as 917764 + 20403289 = 958^2 + 4517^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21321053 - 2²⁴ = 4543837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2651 + ... + 7047.

It is an arithmetic number, because the mean of its divisors is an integer number (2878491).

Almost surely, 2^21321053 is an apocalyptic number.

It is an amenable number.

21321053 is a deficient number, since it is larger than the sum of its proper divisors (1706875).

21321053 is a wasteful number, since it uses less digits than its factorization.

21321053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4783.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21321053 is about 4617.4725770707. The cubic root of 21321053 is about 277.2912826034.

Adding to 21321053 its reverse (35012312), we get a palindrome (56333365).

The spelling of 21321053 in words is "twenty-one million, three hundred twenty-one thousand, fifty-three".