20427409 has 2 divisors, whose sum is σ = 20427410. Its totient is φ = 20427408.

The previous prime is 20427403. The next prime is 20427437. The reversal of 20427409 is 90472402.

It is an a-pointer prime, because the next prime (20427437) can be obtained adding 20427409 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12446784 + 7980625 = 3528^2 + 2825^2 .

It is a cyclic number.

It is not a de Polignac number, because 20427409 - 2⁵ = 20427377 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20427403) 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 as a sum of consecutive naturals, namely, 10213704 + 10213705.

It is an arithmetic number, because the mean of its divisors is an integer number (10213705).

Almost surely, 2^20427409 is an apocalyptic number.

It is an amenable number.

20427409 is a deficient number, since it is larger than the sum of its proper divisors (1).

20427409 is an equidigital number, since it uses as much as digits as its factorization.

20427409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 20427409 is about 4519.6691250577. The cubic root of 20427409 is about 273.3617597179.

The spelling of 20427409 in words is "twenty million, four hundred twenty-seven thousand, four hundred nine".