20561039 has 4 divisors (see below), whose sum is σ = 20589456. Its totient is φ = 20532624.

The previous prime is 20561033. The next prime is 20561053. The reversal of 20561039 is 93016502.

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

It is a cyclic number.

It is not a de Polignac number, because 20561039 - 2²⁰ = 19512463 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20560999 and 20561017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561033) 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, 13094 + ... + 14579.

It is an arithmetic number, because the mean of its divisors is an integer number (5147364).

Almost surely, 2^20561039 is an apocalyptic number.

20561039 is a deficient number, since it is larger than the sum of its proper divisors (28417).

20561039 is an equidigital number, since it uses as much as digits as its factorization.

20561039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28416.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 20561039 is about 4534.4281888679. The cubic root of 20561039 is about 273.9565482449.

The spelling of 20561039 in words is "twenty million, five hundred sixty-one thousand, thirty-nine".