20123421 has 4 divisors (see below), whose sum is σ = 26831232. Its totient is φ = 13415612.

The previous prime is 20123417. The next prime is 20123431. The reversal of 20123421 is 12432102.

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 20123421 - 2² = 20123417 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20123421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20123401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3353901 + ... + 3353906.

It is an arithmetic number, because the mean of its divisors is an integer number (6707808).

Almost surely, 2^20123421 is an apocalyptic number.

It is an amenable number.

20123421 is a deficient number, since it is larger than the sum of its proper divisors (6707811).

20123421 is an equidigital number, since it uses as much as digits as its factorization.

20123421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6707810.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 20123421 is about 4485.9136193199. The cubic root of 20123421 is about 271.9989772525.

Adding to 20123421 its reverse (12432102), we get a palindrome (32555523).

The spelling of 20123421 in words is "twenty million, one hundred twenty-three thousand, four hundred twenty-one".