1866311987 has 2 divisors, whose sum is σ = 1866311988. Its totient is φ = 1866311986.

The previous prime is 1866311983. The next prime is 1866311989. The reversal of 1866311987 is 7891136681.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1866311987 - 2² = 1866311983 is a prime.

Together with 1866311989, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1866311981) 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, 933155993 + 933155994.

It is an arithmetic number, because the mean of its divisors is an integer number (933155994).

Almost surely, 2^1866311987 is an apocalyptic number.

1866311987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1866311987 is an equidigital number, since it uses as much as digits as its factorization.

1866311987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 50.

The square root of 1866311987 is about 43200.8331748359. The cubic root of 1866311987 is about 1231.1985116555.

The spelling of 1866311987 in words is "one billion, eight hundred sixty-six million, three hundred eleven thousand, nine hundred eighty-seven".