7777421857691 has 2 divisors, whose sum is σ = 7777421857692. Its totient is φ = 7777421857690.

The previous prime is 7777421857619. The next prime is 7777421857697. The reversal of 7777421857691 is 1967581247777.

Together with previous prime (7777421857619) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 7777421857691 - 2⁴² = 3379375346587 is a prime.

It is not a weakly prime, because it can be changed into another prime (7777421857697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3888710928845 + 3888710928846.

It is an arithmetic number, because the mean of its divisors is an integer number (3888710928846).

Almost surely, 2^{7777421857691} is an apocalyptic number.

7777421857691 is a deficient number, since it is larger than the sum of its proper divisors (1).

7777421857691 is an equidigital number, since it uses as much as digits as its factorization.

7777421857691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290424960, while the sum is 71.

The spelling of 7777421857691 in words is "seven trillion, seven hundred seventy-seven billion, four hundred twenty-one million, eight hundred fifty-seven thousand, six hundred ninety-one".