866786257721858 has 16 divisors (see below), whose sum is σ = 1368610467544320. Its totient is φ = 410582788104816.

The previous prime is 866786257721851. The next prime is 866786257721861. The reversal of 866786257721858 is 858127752687668.

It is a self number, because there is not a number n which added to its sum of digits gives 866786257721858.

It is not an unprimeable number, because it can be changed into a prime (866786257721851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142806191 + ... + 148752077.

It is an arithmetic number, because the mean of its divisors is an integer number (85538154221520).

Almost surely, 2^{866786257721858} is an apocalyptic number.

866786257721858 is a deficient number, since it is larger than the sum of its proper divisors (501824209822462).

866786257721858 is a wasteful number, since it uses less digits than its factorization.

866786257721858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9782201.

The product of its digits is 30346444800, while the sum is 86.

The spelling of 866786257721858 in words is "eight hundred sixty-six trillion, seven hundred eighty-six billion, two hundred fifty-seven million, seven hundred twenty-one thousand, eight hundred fifty-eight".