20404517 has 4 divisors (see below), whose sum is σ = 23319456. Its totient is φ = 17489580.

The previous prime is 20404493. The next prime is 20404547. The reversal of 20404517 is 71540402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20404517 - 2⁶ = 20404453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20404492 and 20404501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20404547) 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 in 3 ways as a sum of consecutive naturals, for example, 1457459 + ... + 1457472.

It is an arithmetic number, because the mean of its divisors is an integer number (5829864).

Almost surely, 2^20404517 is an apocalyptic number.

It is an amenable number.

20404517 is a deficient number, since it is larger than the sum of its proper divisors (2914939).

20404517 is an equidigital number, since it uses as much as digits as its factorization.

20404517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2914938.

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

The square root of 20404517 is about 4517.1359288824. The cubic root of 20404517 is about 273.2596071564.

Adding to 20404517 its reverse (71540402), we get a palindrome (91944919).

The spelling of 20404517 in words is "twenty million, four hundred four thousand, five hundred seventeen".