20560421 has 4 divisors (see below), whose sum is σ = 23497632. Its totient is φ = 17623212.

The previous prime is 20560403. The next prime is 20560427. The reversal of 20560421 is 12406502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12406502 = 2 ⋅6203251.

It is a cyclic number.

It is not a de Polignac number, because 20560421 - 2¹⁰ = 20559397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20560393 and 20560402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20560427) 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 3 ways as a sum of consecutive naturals, for example, 1468595 + ... + 1468608.

It is an arithmetic number, because the mean of its divisors is an integer number (5874408).

Almost surely, 2^20560421 is an apocalyptic number.

It is an amenable number.

20560421 is a deficient number, since it is larger than the sum of its proper divisors (2937211).

20560421 is an equidigital number, since it uses as much as digits as its factorization.

20560421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2937210.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20560421 is about 4534.3600430491. The cubic root of 20560421 is about 273.9538034607.

Adding to 20560421 its reverse (12406502), we get a palindrome (32966923).

The spelling of 20560421 in words is "twenty million, five hundred sixty thousand, four hundred twenty-one".