7998770778997 has 2 divisors, whose sum is σ = 7998770778998. Its totient is φ = 7998770778996.

The previous prime is 7998770778917. The next prime is 7998770779001.

7998770778997 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7974671010916 + 24099768081 = 2823946^2 + 155241^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 7998770778997 - 2¹¹ = 7998770776949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7998770778917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3999385389498 + 3999385389499.

It is an arithmetic number, because the mean of its divisors is an integer number (3999385389499).

Almost surely, 2^{7998770778997} is an apocalyptic number.

It is an amenable number.

7998770778997 is a deficient number, since it is larger than the sum of its proper divisors (1).

7998770778997 is an equidigital number, since it uses as much as digits as its factorization.

7998770778997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 49401285696, while the sum is 94.

It can be divided in two parts, 79987707 and 78997, that added together give a square (80066704 = 8948²).

The spelling of 7998770778997 in words is "seven trillion, nine hundred ninety-eight billion, seven hundred seventy million, seven hundred seventy-eight thousand, nine hundred ninety-seven".