21053573 has 8 divisors (see below), whose sum is σ = 21403800. Its totient is φ = 20706048.

The previous prime is 21053567. The next prime is 21053597. The reversal of 21053573 is 37535012.

It can be written as a sum of positive squares in 4 ways, for example, as 10543009 + 10510564 = 3247^2 + 3242^2 .

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 21053573 - 2²⁰ = 20004997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21053503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19865 + ... + 20897.

It is an arithmetic number, because the mean of its divisors is an integer number (2675475).

Almost surely, 2^21053573 is an apocalyptic number.

It is an amenable number.

21053573 is a deficient number, since it is larger than the sum of its proper divisors (350227).

21053573 is a wasteful number, since it uses less digits than its factorization.

21053573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1351.

The product of its (nonzero) digits is 3150, while the sum is 26.

The square root of 21053573 is about 4588.4172652452. The cubic root of 21053573 is about 276.1268276945.

Adding to 21053573 its reverse (37535012), we get a palindrome (58588585).

The spelling of 21053573 in words is "twenty-one million, fifty-three thousand, five hundred seventy-three".