20424421 has 2 divisors, whose sum is σ = 20424422. Its totient is φ = 20424420.

The previous prime is 20424409. The next prime is 20424427. The reversal of 20424421 is 12442402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13793796 + 6630625 = 3714^2 + 2575^2 .

It is a cyclic number.

It is not a de Polignac number, because 20424421 - 2¹³ = 20416229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20424427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10212210 + 10212211.

It is an arithmetic number, because the mean of its divisors is an integer number (10212211).

Almost surely, 2^20424421 is an apocalyptic number.

It is an amenable number.

20424421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20424421 is an equidigital number, since it uses as much as digits as its factorization.

20424421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 20424421 is about 4519.3385577980. The cubic root of 20424421 is about 273.3484304901.

Adding to 20424421 its reverse (12442402), we get a palindrome (32866823).

The spelling of 20424421 in words is "twenty million, four hundred twenty-four thousand, four hundred twenty-one".