866668993 has 4 divisors (see below), whose sum is σ = 917649540. Its totient is φ = 815688448.

The previous prime is 866668991. The next prime is 866669039. The reversal of 866668993 is 399866668.

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

It can be written as a sum of positive squares in 2 ways, for example, as 583319104 + 283349889 = 24152^2 + 16833^2 .

It is a cyclic number.

It is not a de Polignac number, because 866668993 - 2¹ = 866668991 is a prime.

It is a super-2 number, since 2×866668993² = 1502230286855268098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866668991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25490248 + ... + 25490281.

It is an arithmetic number, because the mean of its divisors is an integer number (229412385).

Almost surely, 2^866668993 is an apocalyptic number.

It is an amenable number.

866668993 is a deficient number, since it is larger than the sum of its proper divisors (50980547).

866668993 is a wasteful number, since it uses less digits than its factorization.

866668993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50980546.

The product of its digits is 20155392, while the sum is 61.

The square root of 866668993 is about 29439.2423985401. The cubic root of 866668993 is about 953.4203550596.

It can be divided in two parts, 86666 and 8993, that added together give a palindrome (95659).

The spelling of 866668993 in words is "eight hundred sixty-six million, six hundred sixty-eight thousand, nine hundred ninety-three".