206081981 has 8 divisors (see below), whose sum is σ = 240533760. Its totient is φ = 172883088.

The previous prime is 206081977. The next prime is 206081987. The reversal of 206081981 is 189180602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 206081981 - 2² = 206081977 is a prime.

It is a super-2 number, since 2×206081981² = 84939565785768722, 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 (206081987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 312866 + ... + 313523.

It is an arithmetic number, because the mean of its divisors is an integer number (30066720).

Almost surely, 2^206081981 is an apocalyptic number.

It is an amenable number.

206081981 is a deficient number, since it is larger than the sum of its proper divisors (34451779).

206081981 is an equidigital number, since it uses as much as digits as its factorization.

206081981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626443.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 206081981 is about 14355.5557537840. Note that the first 3 decimals coincide. The cubic root of 206081981 is about 590.6723934273.

The spelling of 206081981 in words is "two hundred six million, eighty-one thousand, nine hundred eighty-one".