20409481 has 2 divisors, whose sum is σ = 20409482. Its totient is φ = 20409480.

The previous prime is 20409437. The next prime is 20409497. The reversal of 20409481 is 18490402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20331081 + 78400 = 4509^2 + 280^2 .

It is a cyclic number.

It is not a de Polignac number, because 20409481 - 2⁷ = 20409353 is a prime.

It is a super-2 number, since 2×20409481² = 833093829378722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20400481) 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, 10204740 + 10204741.

It is an arithmetic number, because the mean of its divisors is an integer number (10204741).

Almost surely, 2^20409481 is an apocalyptic number.

It is an amenable number.

20409481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20409481 is an equidigital number, since it uses as much as digits as its factorization.

20409481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 20409481 is about 4517.6853586765. The cubic root of 20409481 is about 273.2817648434.

Adding to 20409481 its reverse (18490402), we get a palindrome (38899883).

The spelling of 20409481 in words is "twenty million, four hundred nine thousand, four hundred eighty-one".