20421431425 has 6 divisors (see below), whose sum is σ = 25322574998. Its totient is φ = 16337145120.

The previous prime is 20421431357. The next prime is 20421431453. The reversal of 20421431425 is 52413412402.

It can be written as a sum of positive squares in 3 ways, for example, as 350475841 + 20070955584 = 18721^2 + 141672^2 .

It is not a de Polignac number, because 20421431425 - 2⁷ = 20421431297 is a prime.

It is a super-2 number, since 2×20421431425² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20421431393 and 20421431402.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 408428604 + ... + 408428653.

Almost surely, 2^20421431425 is an apocalyptic number.

20421431425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20421431425 is a deficient number, since it is larger than the sum of its proper divisors (4901143573).

20421431425 is an equidigital number, since it uses as much as digits as its factorization.

20421431425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816857267 (or 816857262 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 28.

Adding to 20421431425 its reverse (52413412402), we get a palindrome (72834843827).

The spelling of 20421431425 in words is "twenty billion, four hundred twenty-one million, four hundred thirty-one thousand, four hundred twenty-five".