866161557720228 has 384 divisors, whose sum is σ = 2570063478829056. Its totient is φ = 220528248422400.

The previous prime is 866161557720209. The next prime is 866161557720253. The reversal of 866161557720228 is 822027755161668.

It is a super-2 number, since 2×866161557720228² (a number of 31 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 20982066948 + ... + 20982108228.

It is an arithmetic number, because the mean of its divisors is an integer number (6692873642784).

Almost surely, 2^{866161557720228} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 866161557720228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1285031739414528).

866161557720228 is an abundant number, since it is smaller than the sum of its proper divisors (1703901921108828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

866161557720228 is a wasteful number, since it uses less digits than its factorization.

866161557720228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43523 (or 43521 counting only the distinct ones).

The product of its (nonzero) digits is 135475200, while the sum is 66.

The spelling of 866161557720228 in words is "eight hundred sixty-six trillion, one hundred sixty-one billion, five hundred fifty-seven million, seven hundred twenty thousand, two hundred twenty-eight".