20645017 has 8 divisors (see below), whose sum is σ = 21266280. Its totient is φ = 20029440.

The previous prime is 20644997. The next prime is 20645033. The reversal of 20645017 is 71054602.

It can be written as a sum of positive squares in 4 ways, for example, as 24336 + 20620681 = 156^2 + 4541^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20645017 - 2⁷ = 20644889 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20644982 and 20645000.

It is not an unprimeable number, because it can be changed into a prime (20645047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6609 + ... + 9217.

It is an arithmetic number, because the mean of its divisors is an integer number (2658285).

Almost surely, 2^20645017 is an apocalyptic number.

It is an amenable number.

20645017 is a deficient number, since it is larger than the sum of its proper divisors (621263).

20645017 is a wasteful number, since it uses less digits than its factorization.

20645017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2843.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 20645017 is about 4543.6787958657. The cubic root of 20645017 is about 274.3290176210.

Adding to 20645017 its reverse (71054602), we get a palindrome (91699619).

The spelling of 20645017 in words is "twenty million, six hundred forty-five thousand, seventeen".