20530729 has 4 divisors (see below), whose sum is σ = 20742484. Its totient is φ = 20318976.

The previous prime is 20530723. The next prime is 20530759. The reversal of 20530729 is 92703502.

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 14899600 + 5631129 = 3860^2 + 2373^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20530729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20530697 and 20530706.

It is not an unprimeable number, because it can be changed into a prime (20530723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105732 + ... + 105925.

It is an arithmetic number, because the mean of its divisors is an integer number (5185621).

Almost surely, 2^20530729 is an apocalyptic number.

It is an amenable number.

20530729 is a deficient number, since it is larger than the sum of its proper divisors (211755).

20530729 is an equidigital number, since it uses as much as digits as its factorization.

20530729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211754.

The product of its (nonzero) digits is 3780, while the sum is 28.

The square root of 20530729 is about 4531.0847487108. The cubic root of 20530729 is about 273.8218646073.

The spelling of 20530729 in words is "twenty million, five hundred thirty thousand, seven hundred twenty-nine".