20635819 has 2 divisors, whose sum is σ = 20635820. Its totient is φ = 20635818.

The previous prime is 20635817. The next prime is 20635871. The reversal of 20635819 is 91853602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20635819 - 2¹ = 20635817 is a prime.

It is a super-2 number, since 2×20635819² = 851674051601522, which contains 22 as substring.

Together with 20635817, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20635817) 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, 10317909 + 10317910.

It is an arithmetic number, because the mean of its divisors is an integer number (10317910).

Almost surely, 2^20635819 is an apocalyptic number.

20635819 is a deficient number, since it is larger than the sum of its proper divisors (1).

20635819 is an equidigital number, since it uses as much as digits as its factorization.

20635819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 20635819 is about 4542.6665076803. Note that the first 3 decimals coincide. The cubic root of 20635819 is about 274.2882708534.

The spelling of 20635819 in words is "twenty million, six hundred thirty-five thousand, eight hundred nineteen".