205340981 has 2 divisors, whose sum is σ = 205340982. Its totient is φ = 205340980.

The previous prime is 205340957. The next prime is 205341013. The reversal of 205340981 is 189043502.

It is an a-pointer prime, because the next prime (205341013) can be obtained adding 205340981 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125238481 + 80102500 = 11191^2 + 8950^2 .

It is a cyclic number.

It is not a de Polignac number, because 205340981 - 2²² = 201146677 is a prime.

It is a super-2 number, since 2×205340981² = 84329836956084722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205340911) 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 as a sum of consecutive naturals, namely, 102670490 + 102670491.

It is an arithmetic number, because the mean of its divisors is an integer number (102670491).

Almost surely, 2^205340981 is an apocalyptic number.

It is an amenable number.

205340981 is a deficient number, since it is larger than the sum of its proper divisors (1).

205340981 is an equidigital number, since it uses as much as digits as its factorization.

205340981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 205340981 is about 14329.7236888923. The cubic root of 205340981 is about 589.9635915482.

It can be divided in two parts, 2053 and 40981, that added together give a palindrome (43034).

The spelling of 205340981 in words is "two hundred five million, three hundred forty thousand, nine hundred eighty-one".