20731189 has 2 divisors, whose sum is σ = 20731190. Its totient is φ = 20731188.

The previous prime is 20731187. The next prime is 20731231. The reversal of 20731189 is 98113702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15171025 + 5560164 = 3895^2 + 2358^2 .

It is a cyclic number.

It is not a de Polignac number, because 20731189 - 2¹ = 20731187 is a prime.

Together with 20731187, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20731189.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20731187) 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 as a sum of consecutive naturals, namely, 10365594 + 10365595.

It is an arithmetic number, because the mean of its divisors is an integer number (10365595).

Almost surely, 2^20731189 is an apocalyptic number.

It is an amenable number.

20731189 is a deficient number, since it is larger than the sum of its proper divisors (1).

20731189 is an equidigital number, since it uses as much as digits as its factorization.

20731189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 20731189 is about 4553.1515459075. The cubic root of 20731189 is about 274.7101695778.

The spelling of 20731189 in words is "twenty million, seven hundred thirty-one thousand, one hundred eighty-nine".