7777421854991 has 2 divisors, whose sum is σ = 7777421854992. Its totient is φ = 7777421854990.

The previous prime is 7777421854957. The next prime is 7777421854997. The reversal of 7777421854991 is 1994581247777.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7777421854991 is a prime.

It is a super-2 number, since 2×7777421854991² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7777421854997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3888710927495 + 3888710927496.

It is an arithmetic number, because the mean of its divisors is an integer number (3888710927496).

Almost surely, 2^{7777421854991} is an apocalyptic number.

7777421854991 is a deficient number, since it is larger than the sum of its proper divisors (1).

7777421854991 is an equidigital number, since it uses as much as digits as its factorization.

7777421854991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248935680, while the sum is 71.

The spelling of 7777421854991 in words is "seven trillion, seven hundred seventy-seven billion, four hundred twenty-one million, eight hundred fifty-four thousand, nine hundred ninety-one".