205981919 has 16 divisors (see below), whose sum is σ = 245616000. Its totient is φ = 170264160.

The previous prime is 205981913. The next prime is 205981927. The reversal of 205981919 is 919189502.

It is a happy number.

205981919 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 205981919 - 2¹⁶ = 205916383 is a prime.

It is a super-2 number, since 2×205981919² = 84857101909845122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 205981919.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205981913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1169 + ... + 20330.

It is an arithmetic number, because the mean of its divisors is an integer number (15351000).

Almost surely, 2^205981919 is an apocalyptic number.

205981919 is a deficient number, since it is larger than the sum of its proper divisors (39634081).

205981919 is a wasteful number, since it uses less digits than its factorization.

205981919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21590.

The product of its (nonzero) digits is 58320, while the sum is 44.

The square root of 205981919 is about 14352.0701991037. The cubic root of 205981919 is about 590.5767786802.

The spelling of 205981919 in words is "two hundred five million, nine hundred eighty-one thousand, nine hundred nineteen".