128827981 has 4 divisors (see below), whose sum is σ = 128864700. Its totient is φ = 128791264.

The previous prime is 128827943. The next prime is 128828003. The reversal of 128827981 is 189728821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 38862756 + 89965225 = 6234^2 + 9485^2 .

It is a cyclic number.

It is not a de Polignac number, because 128827981 - 2⁹ = 128827469 is a prime.

It is a super-2 number, since 2×128827981² = 33193297377072722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128827901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12466 + ... + 20323.

It is an arithmetic number, because the mean of its divisors is an integer number (32216175).

Almost surely, 2^128827981 is an apocalyptic number.

It is an amenable number.

128827981 is a deficient number, since it is larger than the sum of its proper divisors (36719).

128827981 is an equidigital number, since it uses as much as digits as its factorization.

128827981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36718.

The product of its digits is 129024, while the sum is 46.

The square root of 128827981 is about 11350.2414511763. The cubic root of 128827981 is about 505.0527422612.

The spelling of 128827981 in words is "one hundred twenty-eight million, eight hundred twenty-seven thousand, nine hundred eighty-one".