20686843 has 2 divisors, whose sum is σ = 20686844. Its totient is φ = 20686842.

The previous prime is 20686793. The next prime is 20686847. The reversal of 20686843 is 34868602.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20686843 is a prime.

It is not a weakly prime, because it can be changed into another prime (20686847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10343421 + 10343422.

It is an arithmetic number, because the mean of its divisors is an integer number (10343422).

Almost surely, 2^20686843 is an apocalyptic number.

20686843 is a deficient number, since it is larger than the sum of its proper divisors (1).

20686843 is an equidigital number, since it uses as much as digits as its factorization.

20686843 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 37.

The square root of 20686843 is about 4548.2791251197. The cubic root of 20686843 is about 274.5141526186.

It can be divided in two parts, 2068 and 6843, that added together give a triangular number (8911 = T₁₃₃).

The spelling of 20686843 in words is "twenty million, six hundred eighty-six thousand, eight hundred forty-three".