20891017 has 16 divisors (see below), whose sum is σ = 24780672. Its totient is φ = 17239680.

The previous prime is 20891009. The next prime is 20891027. The reversal of 20891017 is 71019802.

It is not a de Polignac number, because 20891017 - 2³ = 20891009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20891027) 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 15 ways as a sum of consecutive naturals, for example, 23383 + ... + 24259.

It is an arithmetic number, because the mean of its divisors is an integer number (1548792).

Almost surely, 2^20891017 is an apocalyptic number.

It is an amenable number.

20891017 is a deficient number, since it is larger than the sum of its proper divisors (3889655).

20891017 is an equidigital number, since it uses as much as digits as its factorization.

20891017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 20891017 is about 4570.6692070199. The cubic root of 20891017 is about 275.4143264093.

The spelling of 20891017 in words is "twenty million, eight hundred ninety-one thousand, seventeen".