866661039 has 20 divisors (see below), whose sum is σ = 1296553720. Its totient is φ = 576920880.

The previous prime is 866661031. The next prime is 866661049. The reversal of 866661039 is 930166668.

It is not a de Polignac number, because 866661039 - 2³ = 866661031 is a prime.

It is a super-2 number, since 2×866661039² = 1502202713041119042, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 866660985 and 866661003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866661031) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 49884 + ... + 64974.

It is an arithmetic number, because the mean of its divisors is an integer number (64827686).

Almost surely, 2^866661039 is an apocalyptic number.

866661039 is a deficient number, since it is larger than the sum of its proper divisors (429892681).

866661039 is a wasteful number, since it uses less digits than its factorization.

866661039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15812 (or 15803 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 866661039 is about 29439.1073064385. The cubic root of 866661039 is about 953.4174383257.

The spelling of 866661039 in words is "eight hundred sixty-six million, six hundred sixty-one thousand, thirty-nine".