128681947 has 2 divisors, whose sum is σ = 128681948. Its totient is φ = 128681946.

The previous prime is 128681923. The next prime is 128681977. The reversal of 128681947 is 749186821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128681947 - 2¹¹ = 128679899 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 128681897 and 128681906.

It is not a weakly prime, because it can be changed into another prime (128681977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64340973 + 64340974.

It is an arithmetic number, because the mean of its divisors is an integer number (64340974).

Almost surely, 2^128681947 is an apocalyptic number.

128681947 is a deficient number, since it is larger than the sum of its proper divisors (1).

128681947 is an equidigital number, since it uses as much as digits as its factorization.

128681947 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 46.

The square root of 128681947 is about 11343.8065480684. The cubic root of 128681947 is about 504.8618345675.

The spelling of 128681947 in words is "one hundred twenty-eight million, six hundred eighty-one thousand, nine hundred forty-seven".