21058753 has 4 divisors (see below), whose sum is σ = 21075588. Its totient is φ = 21041920.

The previous prime is 21058747. The next prime is 21058757. The reversal of 21058753 is 35785012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6066369 + 14992384 = 2463^2 + 3872^2 .

It is a cyclic number.

It is not a de Polignac number, because 21058753 - 2⁵ = 21058721 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21058757) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6376 + ... + 9097.

It is an arithmetic number, because the mean of its divisors is an integer number (5268897).

Almost surely, 2^21058753 is an apocalyptic number.

It is an amenable number.

21058753 is a deficient number, since it is larger than the sum of its proper divisors (16835).

21058753 is a wasteful number, since it uses less digits than its factorization.

21058753 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16834.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 21058753 is about 4588.9816953220. The cubic root of 21058753 is about 276.1494718268.

The spelling of 21058753 in words is "twenty-one million, fifty-eight thousand, seven hundred fifty-three".