20783858309 has 2 divisors, whose sum is σ = 20783858310. Its totient is φ = 20783858308.

The previous prime is 20783858201. The next prime is 20783858311. The reversal of 20783858309 is 90385838702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14128888225 + 6654970084 = 118865^2 + 81578^2 .

It is a cyclic number.

It is not a de Polignac number, because 20783858309 - 2²⁸ = 20515422853 is a prime.

Together with 20783858311, 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 (20783858609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10391929154 + 10391929155.

It is an arithmetic number, because the mean of its divisors is an integer number (10391929155).

Almost surely, 2^20783858309 is an apocalyptic number.

It is an amenable number.

20783858309 is a deficient number, since it is larger than the sum of its proper divisors (1).

20783858309 is an equidigital number, since it uses as much as digits as its factorization.

20783858309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2903040, while the sum is 53.

The spelling of 20783858309 in words is "twenty billion, seven hundred eighty-three million, eight hundred fifty-eight thousand, three hundred nine".