866121667 has 4 divisors (see below), whose sum is σ = 866391336. Its totient is φ = 865852000.

The previous prime is 866121647. The next prime is 866121671. The reversal of 866121667 is 766121668.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 866121667 - 2⁷ = 866121539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866121647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129958 + ... + 136459.

It is an arithmetic number, because the mean of its divisors is an integer number (216597834).

Almost surely, 2^866121667 is an apocalyptic number.

866121667 is a deficient number, since it is larger than the sum of its proper divisors (269669).

866121667 is a wasteful number, since it uses less digits than its factorization.

866121667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269668.

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

The square root of 866121667 is about 29429.9450730034. The cubic root of 866121667 is about 953.2196088145.

Subtracting from 866121667 its reverse (766121668), we obtain a palindrome (99999999).

The spelling of 866121667 in words is "eight hundred sixty-six million, one hundred twenty-one thousand, six hundred sixty-seven".