20858117 has 4 divisors (see below), whose sum is σ = 23837856. Its totient is φ = 17878380.

The previous prime is 20858111. The next prime is 20858119. The reversal of 20858117 is 71185802.

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: 71185802 = 2 ⋅35592901.

It is a cyclic number.

It is not a de Polignac number, because 20858117 - 2¹⁸ = 20595973 is a prime.

It is a super-2 number, since 2×20858117² = 870122089571378, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20858111) 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 3 ways as a sum of consecutive naturals, for example, 1489859 + ... + 1489872.

It is an arithmetic number, because the mean of its divisors is an integer number (5959464).

Almost surely, 2^20858117 is an apocalyptic number.

It is an amenable number.

20858117 is a deficient number, since it is larger than the sum of its proper divisors (2979739).

20858117 is an equidigital number, since it uses as much as digits as its factorization.

20858117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2979738.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 20858117 is about 4567.0687535880. The cubic root of 20858117 is about 275.2696726551.

The spelling of 20858117 in words is "twenty million, eight hundred fifty-eight thousand, one hundred seventeen".