128681977 has 2 divisors, whose sum is σ = 128681978. Its totient is φ = 128681976.

The previous prime is 128681947. The next prime is 128681999. The reversal of 128681977 is 779186821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79905721 + 48776256 = 8939^2 + 6984^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128681977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128681977.

It is not a weakly prime, because it can be changed into another prime (128681947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64340988 + 64340989.

It is an arithmetic number, because the mean of its divisors is an integer number (64340989).

Almost surely, 2^128681977 is an apocalyptic number.

It is an amenable number.

128681977 is a deficient number, since it is larger than the sum of its proper divisors (1).

128681977 is an equidigital number, since it uses as much as digits as its factorization.

128681977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 338688, while the sum is 49.

The square root of 128681977 is about 11343.8078703758. The cubic root of 128681977 is about 504.8618738008.

The spelling of 128681977 in words is "one hundred twenty-eight million, six hundred eighty-one thousand, nine hundred seventy-seven".