20543689 has 2 divisors, whose sum is σ = 20543690. Its totient is φ = 20543688.

The previous prime is 20543671. The next prime is 20543711. The reversal of 20543689 is 98634502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19316025 + 1227664 = 4395^2 + 1108^2 .

It is a cyclic number.

It is not a de Polignac number, because 20543689 - 2⁵ = 20543657 is a prime.

It is not a weakly prime, because it can be changed into another prime (20543609) 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, 10271844 + 10271845.

It is an arithmetic number, because the mean of its divisors is an integer number (10271845).

Almost surely, 2^20543689 is an apocalyptic number.

It is an amenable number.

20543689 is a deficient number, since it is larger than the sum of its proper divisors (1).

20543689 is an equidigital number, since it uses as much as digits as its factorization.

20543689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 20543689 is about 4532.5146442124. The cubic root of 20543689 is about 273.8794690712.

The spelling of 20543689 in words is "twenty million, five hundred forty-three thousand, six hundred eighty-nine".