20305861 has 2 divisors, whose sum is σ = 20305862. Its totient is φ = 20305860.

The previous prime is 20305843. The next prime is 20305897. The reversal of 20305861 is 16850302.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19412836 + 893025 = 4406^2 + 945^2 .

It is a cyclic number.

It is not a de Polignac number, because 20305861 - 2⁹ = 20305349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20305811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10152930 + 10152931.

It is an arithmetic number, because the mean of its divisors is an integer number (10152931).

Almost surely, 2^20305861 is an apocalyptic number.

It is an amenable number.

20305861 is a deficient number, since it is larger than the sum of its proper divisors (1).

20305861 is an equidigital number, since it uses as much as digits as its factorization.

20305861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 20305861 is about 4506.2025032171. The cubic root of 20305861 is about 272.8184913421.

The spelling of 20305861 in words is "twenty million, three hundred five thousand, eight hundred sixty-one".