205909091 has 2 divisors, whose sum is σ = 205909092. Its totient is φ = 205909090.

The previous prime is 205909079. The next prime is 205909127. The reversal of 205909091 is 190909502.

205909091 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205909091 is a prime.

It is a super-3 number, since 3×205909091³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (205909001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102954545 + 102954546.

It is an arithmetic number, because the mean of its divisors is an integer number (102954546).

Almost surely, 2^205909091 is an apocalyptic number.

205909091 is a deficient number, since it is larger than the sum of its proper divisors (1).

205909091 is an equidigital number, since it uses as much as digits as its factorization.

205909091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7290, while the sum is 35.

The square root of 205909091 is about 14349.5327798504. The cubic root of 205909091 is about 590.5071680467.

The spelling of 205909091 in words is "two hundred five million, nine hundred nine thousand, ninety-one".