20851353779 has 2 divisors, whose sum is σ = 20851353780. Its totient is φ = 20851353778.

The previous prime is 20851353751. The next prime is 20851353781. The reversal of 20851353779 is 97735315802.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20851353779 is a prime.

Together with 20851353781, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20851353739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10425676889 + 10425676890.

It is an arithmetic number, because the mean of its divisors is an integer number (10425676890).

Almost surely, 2^20851353779 is an apocalyptic number.

20851353779 is a deficient number, since it is larger than the sum of its proper divisors (1).

20851353779 is an equidigital number, since it uses as much as digits as its factorization.

20851353779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1587600, while the sum is 50.

The spelling of 20851353779 in words is "twenty billion, eight hundred fifty-one million, three hundred fifty-three thousand, seven hundred seventy-nine".