128681881 has 2 divisors, whose sum is σ = 128681882. Its totient is φ = 128681880.

The previous prime is 128681873. The next prime is 128681909. The reversal of 128681881 is 188186821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121440400 + 7241481 = 11020^2 + 2691^2 .

It is a cyclic number.

It is not a de Polignac number, because 128681881 - 2³ = 128681873 is a prime.

It is a super-2 number, since 2×128681881² = 33118052995396322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (128681831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64340940 + 64340941.

It is an arithmetic number, because the mean of its divisors is an integer number (64340941).

Almost surely, 2^128681881 is an apocalyptic number.

It is an amenable number.

128681881 is a deficient number, since it is larger than the sum of its proper divisors (1).

128681881 is an equidigital number, since it uses as much as digits as its factorization.

128681881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49152, while the sum is 43.

The square root of 128681881 is about 11343.8036389916. The cubic root of 128681881 is about 504.8617482543.

The spelling of 128681881 in words is "one hundred twenty-eight million, six hundred eighty-one thousand, eight hundred eighty-one".