1977697769 has 2 divisors, whose sum is σ = 1977697770. Its totient is φ = 1977697768.

The previous prime is 1977697741. The next prime is 1977697781. The reversal of 1977697769 is 9677967791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1063542544 + 914155225 = 32612^2 + 30235^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1977697769 is a prime.

It is a super-3 number, since 3×1977697769³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1977697699 and 1977697708.

It is not a weakly prime, because it can be changed into another prime (1977697069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 988848884 + 988848885.

It is an arithmetic number, because the mean of its divisors is an integer number (988848885).

Almost surely, 2^1977697769 is an apocalyptic number.

It is an amenable number.

1977697769 is a deficient number, since it is larger than the sum of its proper divisors (1).

1977697769 is an equidigital number, since it uses as much as digits as its factorization.

1977697769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63011844, while the sum is 68.

The square root of 1977697769 is about 44471.3140012750. The cubic root of 1977697769 is about 1255.2203586543.

The spelling of 1977697769 in words is "one billion, nine hundred seventy-seven million, six hundred ninety-seven thousand, seven hundred sixty-nine".