866123857473839 has 16 divisors (see below), whose sum is σ = 902440424944800. Its totient is φ = 830237361913344.

The previous prime is 866123857473821. The next prime is 866123857473859. The reversal of 866123857473839 is 938374758321668.

It is not a de Polignac number, because 866123857473839 - 2¹² = 866123857469743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866123857473859) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1218203819 + ... + 1218914595.

It is an arithmetic number, because the mean of its divisors is an integer number (56402526559050).

Almost surely, 2^{866123857473839} is an apocalyptic number.

866123857473839 is a deficient number, since it is larger than the sum of its proper divisors (36316567470961).

866123857473839 is a wasteful number, since it uses less digits than its factorization.

866123857473839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1013242.

The product of its digits is 8778792960, while the sum is 80.

The spelling of 866123857473839 in words is "eight hundred sixty-six trillion, one hundred twenty-three billion, eight hundred fifty-seven million, four hundred seventy-three thousand, eight hundred thirty-nine".