206405491 has 2 divisors, whose sum is σ = 206405492. Its totient is φ = 206405490.

The previous prime is 206405477. The next prime is 206405497. The reversal of 206405491 is 194504602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 206405491 - 2¹³ = 206397299 is a prime.

It is not a weakly prime, because it can be changed into another prime (206405497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103202745 + 103202746.

It is an arithmetic number, because the mean of its divisors is an integer number (103202746).

Almost surely, 2^206405491 is an apocalyptic number.

206405491 is a deficient number, since it is larger than the sum of its proper divisors (1).

206405491 is an equidigital number, since it uses as much as digits as its factorization.

206405491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 206405491 is about 14366.8190981859. The cubic root of 206405491 is about 590.9813134037.

The spelling of 206405491 in words is "two hundred six million, four hundred five thousand, four hundred ninety-one".