20105447 has 2 divisors, whose sum is σ = 20105448. Its totient is φ = 20105446.

The previous prime is 20105443. The next prime is 20105479. The reversal of 20105447 is 74450102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20105447 - 2² = 20105443 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20105443) 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, 10052723 + 10052724.

It is an arithmetic number, because the mean of its divisors is an integer number (10052724).

Almost surely, 2^20105447 is an apocalyptic number.

20105447 is a deficient number, since it is larger than the sum of its proper divisors (1).

20105447 is an equidigital number, since it uses as much as digits as its factorization.

20105447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 20105447 is about 4483.9097894583. The cubic root of 20105447 is about 271.9179710473.

Adding to 20105447 its reverse (74450102), we get a palindrome (94555549).

The spelling of 20105447 in words is "twenty million, one hundred five thousand, four hundred forty-seven".