866123857473838 has 4 divisors (see below), whose sum is σ = 1299185786210760. Its totient is φ = 433061928736918.

The previous prime is 866123857473821. The next prime is 866123857473859. The reversal of 866123857473838 is 838374758321668.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×866123857473838² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 216530964368458 + ... + 216530964368461.

It is an arithmetic number, because the mean of its divisors is an integer number (324796446552690).

Almost surely, 2^{866123857473838} is an apocalyptic number.

866123857473838 is a deficient number, since it is larger than the sum of its proper divisors (433061928736922).

866123857473838 is a wasteful number, since it uses less digits than its factorization.

866123857473838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433061928736921.

The product of its digits is 7803371520, while the sum is 79.

The spelling of 866123857473838 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-eight".