206315891 has 2 divisors, whose sum is σ = 206315892. Its totient is φ = 206315890.

The previous prime is 206315869. The next prime is 206315897. The reversal of 206315891 is 198513602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 206315891 - 2¹⁸ = 206053747 is a prime.

It is not a weakly prime, because it can be changed into another prime (206315897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103157945 + 103157946.

It is an arithmetic number, because the mean of its divisors is an integer number (103157946).

Almost surely, 2^206315891 is an apocalyptic number.

206315891 is a deficient number, since it is larger than the sum of its proper divisors (1).

206315891 is an equidigital number, since it uses as much as digits as its factorization.

206315891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 206315891 is about 14363.7004633207. The cubic root of 206315891 is about 590.8957866260.

The spelling of 206315891 in words is "two hundred six million, three hundred fifteen thousand, eight hundred ninety-one".