206981 has 4 divisors (see below), whose sum is σ = 208032. Its totient is φ = 205932.

The previous prime is 206953. The next prime is 206993. The reversal of 206981 is 189602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 206981 - 2⁶ = 206917 is a prime.

It is a super-2 number, since 2×206981² = 85682268722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 206981.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 206981.

It is not an unprimeable number, because it can be changed into a prime (206911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131 + ... + 656.

It is an arithmetic number, because the mean of its divisors is an integer number (52008).

2²⁰⁶⁹⁸¹ is an apocalyptic number.

206981 is the 263-rd octagonal number.

It is an amenable number.

206981 is a deficient number, since it is larger than the sum of its proper divisors (1051).

206981 is an equidigital number, since it uses as much as digits as its factorization.

206981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 206981 is about 454.9516457823. The cubic root of 206981 is about 59.1530070519.

The spelling of 206981 in words is "two hundred six thousand, nine hundred eighty-one".