20846729 has 2 divisors, whose sum is σ = 20846730. Its totient is φ = 20846728.

The previous prime is 20846713. The next prime is 20846731. The reversal of 20846729 is 92764802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20720704 + 126025 = 4552^2 + 355^2 .

It is a cyclic number.

It is not a de Polignac number, because 20846729 - 2⁴ = 20846713 is a prime.

It is a super-2 number, since 2×20846729² = 869172219998882, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 20846731, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20846692 and 20846701.

It is not a weakly prime, because it can be changed into another prime (20846129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10423364 + 10423365.

It is an arithmetic number, because the mean of its divisors is an integer number (10423365).

Almost surely, 2^20846729 is an apocalyptic number.

It is an amenable number.

20846729 is a deficient number, since it is larger than the sum of its proper divisors (1).

20846729 is an equidigital number, since it uses as much as digits as its factorization.

20846729 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 20846729 is about 4565.8218318283. The cubic root of 20846729 is about 275.2195667945.

The spelling of 20846729 in words is "twenty million, eight hundred forty-six thousand, seven hundred twenty-nine".