20861378851 has 2 divisors, whose sum is σ = 20861378852. Its totient is φ = 20861378850.

The previous prime is 20861378819. The next prime is 20861378869. The reversal of 20861378851 is 15887316802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20861378851 - 2⁵ = 20861378819 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20861378795 and 20861378804.

It is not a weakly prime, because it can be changed into another prime (20861370851) 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, 10430689425 + 10430689426.

It is an arithmetic number, because the mean of its divisors is an integer number (10430689426).

Almost surely, 2^20861378851 is an apocalyptic number.

20861378851 is a deficient number, since it is larger than the sum of its proper divisors (1).

20861378851 is an equidigital number, since it uses as much as digits as its factorization.

20861378851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 645120, while the sum is 49.

The spelling of 20861378851 in words is "twenty billion, eight hundred sixty-one million, three hundred seventy-eight thousand, eight hundred fifty-one".