20843689 has 2 divisors, whose sum is σ = 20843690. Its totient is φ = 20843688.

The previous prime is 20843677. The next prime is 20843723. The reversal of 20843689 is 98634802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17264025 + 3579664 = 4155^2 + 1892^2 .

It is a cyclic number.

It is not a de Polignac number, because 20843689 - 2⁵ = 20843657 is a prime.

It is a super-2 number, since 2×20843689² = 868918742257442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20843629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10421844 + 10421845.

It is an arithmetic number, because the mean of its divisors is an integer number (10421845).

Almost surely, 2^20843689 is an apocalyptic number.

It is an amenable number.

20843689 is a deficient number, since it is larger than the sum of its proper divisors (1).

20843689 is an equidigital number, since it uses as much as digits as its factorization.

20843689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944, while the sum is 40.

The square root of 20843689 is about 4565.4889113873. The cubic root of 20843689 is about 275.2061880665.

The spelling of 20843689 in words is "twenty million, eight hundred forty-three thousand, six hundred eighty-nine".