20545447 has 4 divisors (see below), whose sum is σ = 22125880. Its totient is φ = 18965016.

The previous prime is 20545433. The next prime is 20545477. The reversal of 20545447 is 74454502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20545447 - 2¹⁹ = 20021159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20545477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 790197 + ... + 790222.

It is an arithmetic number, because the mean of its divisors is an integer number (5531470).

Almost surely, 2^20545447 is an apocalyptic number.

20545447 is a deficient number, since it is larger than the sum of its proper divisors (1580433).

20545447 is a wasteful number, since it uses less digits than its factorization.

20545447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1580432.

The product of its (nonzero) digits is 22400, while the sum is 31.

The square root of 20545447 is about 4532.7085721454. The cubic root of 20545447 is about 273.8872811439.

Adding to 20545447 its reverse (74454502), we get a palindrome (94999949).

The spelling of 20545447 in words is "twenty million, five hundred forty-five thousand, four hundred forty-seven".