20404420421 has 16 divisors (see below), whose sum is σ = 25457241600. Its totient is φ = 15888320880.

The previous prime is 20404420411. The next prime is 20404420507. The reversal of 20404420421 is 12402440402.

It is a cyclic number.

It is not a de Polignac number, because 20404420421 - 2¹⁰ = 20404419397 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20404420411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17030 + ... + 202728.

It is an arithmetic number, because the mean of its divisors is an integer number (1591077600).

Almost surely, 2^20404420421 is an apocalyptic number.

It is an amenable number.

20404420421 is a deficient number, since it is larger than the sum of its proper divisors (5052821179).

20404420421 is a wasteful number, since it uses less digits than its factorization.

20404420421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187144.

The product of its (nonzero) digits is 2048, while the sum is 23.

Adding to 20404420421 its reverse (12402440402), we get a palindrome (32806860823).

The spelling of 20404420421 in words is "twenty billion, four hundred four million, four hundred twenty thousand, four hundred twenty-one".