20504421 has 60 divisors (see below), whose sum is σ = 37097632. Its totient is φ = 11049696.

The previous prime is 20504417. The next prime is 20504437. The reversal of 20504421 is 12440502.

It is not a de Polignac number, because 20504421 - 2² = 20504417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20504394 and 20504403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20504411) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 476826 + ... + 476868.

Almost surely, 2^20504421 is an apocalyptic number.

20504421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20504421 is a deficient number, since it is larger than the sum of its proper divisors (16593211).

20504421 is an equidigital number, since it uses as much as digits as its factorization.

20504421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 20504421 is about 4528.1807605262. The cubic root of 20504421 is about 273.7048565079.

Adding to 20504421 its reverse (12440502), we get a palindrome (32944923).

The spelling of 20504421 in words is "twenty million, five hundred four thousand, four hundred twenty-one".