206128881 has 24 divisors (see below), whose sum is σ = 352881984. Its totient is φ = 117786960.

The previous prime is 206128877. The next prime is 206128883. The reversal of 206128881 is 188821602.

It is not a de Polignac number, because 206128881 - 2² = 206128877 is a prime.

It is a super-2 number, since 2×206128881² = 84978231164624322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (206128883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58890 + ... + 62291.

It is an arithmetic number, because the mean of its divisors is an integer number (14703416).

Almost surely, 2^206128881 is an apocalyptic number.

206128881 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

206128881 is a deficient number, since it is larger than the sum of its proper divisors (146753103).

206128881 is an equidigital number, since it uses as much as digits as its factorization.

206128881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121203 (or 121191 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 206128881 is about 14357.1891747654. The cubic root of 206128881 is about 590.7171983052.

The spelling of 206128881 in words is "two hundred six million, one hundred twenty-eight thousand, eight hundred eighty-one".