206831987 has 2 divisors, whose sum is σ = 206831988. Its totient is φ = 206831986.

The previous prime is 206831983. The next prime is 206832001. The reversal of 206831987 is 789138602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 206831987 - 2² = 206831983 is a prime.

It is not a weakly prime, because it can be changed into another prime (206831981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103415993 + 103415994.

It is an arithmetic number, because the mean of its divisors is an integer number (103415994).

Almost surely, 2^206831987 is an apocalyptic number.

206831987 is a deficient number, since it is larger than the sum of its proper divisors (1).

206831987 is an equidigital number, since it uses as much as digits as its factorization.

206831987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 206831987 is about 14381.6545292953. The cubic root of 206831987 is about 591.3880819114.

The spelling of 206831987 in words is "two hundred six million, eight hundred thirty-one thousand, nine hundred eighty-seven".