266431987 has 2 divisors, whose sum is σ = 266431988. Its totient is φ = 266431986.

The previous prime is 266431897. The next prime is 266431993. The reversal of 266431987 is 789134662.

Together with previous prime (266431897) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 266431987 - 2⁷ = 266431859 is a prime.

It is not a weakly prime, because it can be changed into another prime (266432987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133215993 + 133215994.

It is an arithmetic number, because the mean of its divisors is an integer number (133215994).

Almost surely, 2^266431987 is an apocalyptic number.

266431987 is a deficient number, since it is larger than the sum of its proper divisors (1).

266431987 is an equidigital number, since it uses as much as digits as its factorization.

266431987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 46.

The square root of 266431987 is about 16322.7444689917. The cubic root of 266431987 is about 643.4707170481.

The spelling of 266431987 in words is "two hundred sixty-six million, four hundred thirty-one thousand, nine hundred eighty-seven".