20005423121 has 4 divisors (see below), whose sum is σ = 20021916852. Its totient is φ = 19988929392.

The previous prime is 20005423117. The next prime is 20005423153. The reversal of 20005423121 is 12132450002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12132450002 = 2 ⋅6066225001.

It can be written as a sum of positive squares in 2 ways, for example, as 1498541521 + 18506881600 = 38711^2 + 136040^2 .

It is a cyclic number.

It is not a de Polignac number, because 20005423121 - 2² = 20005423117 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20005423093 and 20005423102.

It is not an unprimeable number, because it can be changed into a prime (20005429121) 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, 8245046 + ... + 8247471.

It is an arithmetic number, because the mean of its divisors is an integer number (5005479213).

Almost surely, 2^20005423121 is an apocalyptic number.

It is an amenable number.

20005423121 is a deficient number, since it is larger than the sum of its proper divisors (16493731).

20005423121 is a wasteful number, since it uses less digits than its factorization.

20005423121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16493730.

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

Adding to 20005423121 its reverse (12132450002), we get a palindrome (32137873123).

The spelling of 20005423121 in words is "twenty billion, five million, four hundred twenty-three thousand, one hundred twenty-one".