285861991 has 2 divisors, whose sum is σ = 285861992. Its totient is φ = 285861990.

The previous prime is 285861959. The next prime is 285861997. The reversal of 285861991 is 199168582.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 285861991 - 2⁵ = 285861959 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (285861997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 142930995 + 142930996.

It is an arithmetic number, because the mean of its divisors is an integer number (142930996).

Almost surely, 2^285861991 is an apocalyptic number.

285861991 is a deficient number, since it is larger than the sum of its proper divisors (1).

285861991 is an equidigital number, since it uses as much as digits as its factorization.

285861991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 49.

The square root of 285861991 is about 16907.4537113073. The cubic root of 285861991 is about 658.7472340907.

The spelling of 285861991 in words is "two hundred eighty-five million, eight hundred sixty-one thousand, nine hundred ninety-one".