20636309 has 2 divisors, whose sum is σ = 20636310. Its totient is φ = 20636308.

The previous prime is 20636303. The next prime is 20636311. The reversal of 20636309 is 90363602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10745284 + 9891025 = 3278^2 + 3145^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20636309 is a prime.

Together with 20636311, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20636303) 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, 10318154 + 10318155.

It is an arithmetic number, because the mean of its divisors is an integer number (10318155).

Almost surely, 2^20636309 is an apocalyptic number.

It is an amenable number.

20636309 is a deficient number, since it is larger than the sum of its proper divisors (1).

20636309 is an equidigital number, since it uses as much as digits as its factorization.

20636309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 29.

The square root of 20636309 is about 4542.7204404409. The cubic root of 20636309 is about 274.2904418389.

The spelling of 20636309 in words is "twenty million, six hundred thirty-six thousand, three hundred nine".