20405017 has 4 divisors (see below), whose sum is σ = 20615476. Its totient is φ = 20194560.

The previous prime is 20404999. The next prime is 20405027. The reversal of 20405017 is 71050402.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12503296 + 7901721 = 3536^2 + 2811^2 .

It is a cyclic number.

It is not a de Polignac number, because 20405017 - 2⁷ = 20404889 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20404985 and 20405003.

It is not an unprimeable number, because it can be changed into a prime (20405027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105084 + ... + 105277.

It is an arithmetic number, because the mean of its divisors is an integer number (5153869).

Almost surely, 2^20405017 is an apocalyptic number.

It is an amenable number.

20405017 is a deficient number, since it is larger than the sum of its proper divisors (210459).

20405017 is an equidigital number, since it uses as much as digits as its factorization.

20405017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210458.

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 20405017 is about 4517.1912733467. The cubic root of 20405017 is about 273.2618391571.

Adding to 20405017 its reverse (71050402), we get a palindrome (91455419).

The spelling of 20405017 in words is "twenty million, four hundred five thousand, seventeen".