20870017 has 4 divisors (see below), whose sum is σ = 23851456. Its totient is φ = 17888580.

The previous prime is 20869987. The next prime is 20870023. The reversal of 20870017 is 71007802.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 71007802 = 2 ⋅35503901.

It is a cyclic number.

It is not a de Polignac number, because 20870017 - 2⁷ = 20869889 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20869973 and 20870000.

It is not an unprimeable number, because it can be changed into a prime (20870077) 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, 1490709 + ... + 1490722.

It is an arithmetic number, because the mean of its divisors is an integer number (5962864).

Almost surely, 2^20870017 is an apocalyptic number.

It is an amenable number.

20870017 is a deficient number, since it is larger than the sum of its proper divisors (2981439).

20870017 is an equidigital number, since it uses as much as digits as its factorization.

20870017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2981438.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 20870017 is about 4568.3713728199. The cubic root of 20870017 is about 275.3220117732.

Adding to 20870017 its reverse (71007802), we get a palindrome (91877819).

It can be divided in two parts, 208 and 70017, that added together give a square (70225 = 265²).

The spelling of 20870017 in words is "twenty million, eight hundred seventy thousand, seventeen".