20405343416321 has 4 divisors (see below), whose sum is σ = 20879886286512. Its totient is φ = 19930800546132.

The previous prime is 20405343416303. The next prime is 20405343416329. The reversal of 20405343416321 is 12361434350402.

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.

It is a cyclic number.

It is not a de Polignac number, because 20405343416321 - 2²⁶ = 20405276307457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20405343416329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 237271435031 + ... + 237271435116.

It is an arithmetic number, because the mean of its divisors is an integer number (5219971571628).

Almost surely, 2^{20405343416321} is an apocalyptic number.

It is an amenable number.

20405343416321 is a deficient number, since it is larger than the sum of its proper divisors (474542870191).

20405343416321 is an equidigital number, since it uses as much as digits as its factorization.

20405343416321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474542870190.

The product of its (nonzero) digits is 207360, while the sum is 38.

Adding to 20405343416321 its reverse (12361434350402), we get a palindrome (32766777766723).

The spelling of 20405343416321 in words is "twenty trillion, four hundred five billion, three hundred forty-three million, four hundred sixteen thousand, three hundred twenty-one".