861331687 has 2 divisors, whose sum is σ = 861331688. Its totient is φ = 861331686.

The previous prime is 861331661. The next prime is 861331733. The reversal of 861331687 is 786133168.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861331687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861331607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430665843 + 430665844.

It is an arithmetic number, because the mean of its divisors is an integer number (430665844).

Almost surely, 2^861331687 is an apocalyptic number.

861331687 is a deficient number, since it is larger than the sum of its proper divisors (1).

861331687 is an equidigital number, since it uses as much as digits as its factorization.

861331687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 43.

The square root of 861331687 is about 29348.4528893773. The cubic root of 861331687 is about 951.4591379521.

The spelling of 861331687 in words is "eight hundred sixty-one million, three hundred thirty-one thousand, six hundred eighty-seven".