20378766878777 has 2 divisors, whose sum is σ = 20378766878778. Its totient is φ = 20378766878776.

The previous prime is 20378766878753. The next prime is 20378766878809. The reversal of 20378766878777 is 77787866787302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15380036784121 + 4998730094656 = 3921739^2 + 2235784^2 .

It is a cyclic number.

It is not a de Polignac number, because 20378766878777 - 2¹⁶ = 20378766813241 is a prime.

It is a super-2 number, since 2×20378766878777² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20378766878695 and 20378766878704.

It is not a weakly prime, because it can be changed into another prime (20378766878707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10189383439388 + 10189383439389.

It is an arithmetic number, because the mean of its divisors is an integer number (10189383439389).

Almost surely, 2^{20378766878777} is an apocalyptic number.

It is an amenable number.

20378766878777 is a deficient number, since it is larger than the sum of its proper divisors (1).

20378766878777 is an equidigital number, since it uses as much as digits as its factorization.

20378766878777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13011038208, while the sum is 83.

The spelling of 20378766878777 in words is "twenty trillion, three hundred seventy-eight billion, seven hundred sixty-six million, eight hundred seventy-eight thousand, seven hundred seventy-seven".