20400323421 has 4 divisors (see below), whose sum is σ = 27200431232. Its totient is φ = 13600215612.

The previous prime is 20400323401. The next prime is 20400323431. The reversal of 20400323421 is 12432300402.

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 not a de Polignac number, because 20400323421 - 2²⁷ = 20266105693 is a prime.

It is a super-2 number, since 2×20400323421² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400323401) 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, 3400053901 + ... + 3400053906.

It is an arithmetic number, because the mean of its divisors is an integer number (6800107808).

Almost surely, 2^20400323421 is an apocalyptic number.

It is an amenable number.

20400323421 is a deficient number, since it is larger than the sum of its proper divisors (6800107811).

20400323421 is an equidigital number, since it uses as much as digits as its factorization.

20400323421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6800107810.

The product of its (nonzero) digits is 1152, while the sum is 21.

Adding to 20400323421 its reverse (12432300402), we get a palindrome (32832623823).

The spelling of 20400323421 in words is "twenty billion, four hundred million, three hundred twenty-three thousand, four hundred twenty-one".