20005125421 has 4 divisors (see below), whose sum is σ = 20078945344. Its totient is φ = 19931305500.

The previous prime is 20005125409. The next prime is 20005125451. The reversal of 20005125421 is 12452150002.

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: 12452150002 = 2 ⋅6226075001.

It is a cyclic number.

It is not a de Polignac number, because 20005125421 - 2⁵ = 20005125389 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20005125392 and 20005125401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20005125401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36909555 + ... + 36910096.

It is an arithmetic number, because the mean of its divisors is an integer number (5019736336).

Almost surely, 2^20005125421 is an apocalyptic number.

It is an amenable number.

20005125421 is a deficient number, since it is larger than the sum of its proper divisors (73819923).

20005125421 is an equidigital number, since it uses as much as digits as its factorization.

20005125421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73819922.

The product of its (nonzero) digits is 800, while the sum is 22.

Adding to 20005125421 its reverse (12452150002), we get a palindrome (32457275423).

The spelling of 20005125421 in words is "twenty billion, five million, one hundred twenty-five thousand, four hundred twenty-one".