6171977921 has 2 divisors, whose sum is σ = 6171977922. Its totient is φ = 6171977920.

The previous prime is 6171977893. The next prime is 6171977969. The reversal of 6171977921 is 1297791716.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5649626896 + 522351025 = 75164^2 + 22855^2 .

It is a cyclic number.

It is not a de Polignac number, because 6171977921 - 2¹⁰ = 6171976897 is a prime.

It is a super-3 number, since 3×6171977921³ (a number of 30 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 6171977921.

It is not a weakly prime, because it can be changed into another prime (6171977971) 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, 3085988960 + 3085988961.

It is an arithmetic number, because the mean of its divisors is an integer number (3085988961).

Almost surely, 2^6171977921 is an apocalyptic number.

It is an amenable number.

6171977921 is a deficient number, since it is larger than the sum of its proper divisors (1).

6171977921 is an equidigital number, since it uses as much as digits as its factorization.

6171977921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 333396, while the sum is 50.

The square root of 6171977921 is about 78561.9368460325. The cubic root of 6171977921 is about 1834.3186764458.

The spelling of 6171977921 in words is "six billion, one hundred seventy-one million, nine hundred seventy-seven thousand, nine hundred twenty-one".