20421431453 has 2 divisors, whose sum is σ = 20421431454. Its totient is φ = 20421431452.

The previous prime is 20421431357. The next prime is 20421431479. The reversal of 20421431453 is 35413412402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14489659129 + 5931772324 = 120373^2 + 77018^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421431453 - 2²⁶ = 20354322589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20421431483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210715726 + 10210715727.

It is an arithmetic number, because the mean of its divisors is an integer number (10210715727).

Almost surely, 2^20421431453 is an apocalyptic number.

It is an amenable number.

20421431453 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421431453 is an equidigital number, since it uses as much as digits as its factorization.

20421431453 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 29.

Adding to 20421431453 its reverse (35413412402), we get a palindrome (55834843855).

The spelling of 20421431453 in words is "twenty billion, four hundred twenty-one million, four hundred thirty-one thousand, four hundred fifty-three".