128386981 has 2 divisors, whose sum is σ = 128386982. Its totient is φ = 128386980.

The previous prime is 128386931. The next prime is 128386987. The reversal of 128386981 is 189683821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83429956 + 44957025 = 9134^2 + 6705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128386981 is a prime.

It is a super-2 number, since 2×128386981² = 32966433780588722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128386987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64193490 + 64193491.

It is an arithmetic number, because the mean of its divisors is an integer number (64193491).

Almost surely, 2^128386981 is an apocalyptic number.

It is an amenable number.

128386981 is a deficient number, since it is larger than the sum of its proper divisors (1).

128386981 is an equidigital number, since it uses as much as digits as its factorization.

128386981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 165888, while the sum is 46.

The square root of 128386981 is about 11330.7978977652. The cubic root of 128386981 is about 504.4757897298.

The spelling of 128386981 in words is "one hundred twenty-eight million, three hundred eighty-six thousand, nine hundred eighty-one".