666800839 has 4 divisors (see below), whose sum is σ = 701895640. Its totient is φ = 631706040.

The previous prime is 666800837. The next prime is 666800899. The reversal of 666800839 is 938008666.

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 666800839 - 2¹ = 666800837 is a prime.

It is a super-2 number, since 2×666800839² = 889246717782207842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666800833) 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, 17547372 + ... + 17547409.

It is an arithmetic number, because the mean of its divisors is an integer number (175473910).

Almost surely, 2^666800839 is an apocalyptic number.

666800839 is a deficient number, since it is larger than the sum of its proper divisors (35094801).

666800839 is a wasteful number, since it uses less digits than its factorization.

666800839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35094800.

The product of its (nonzero) digits is 373248, while the sum is 46.

The square root of 666800839 is about 25822.4870800626. The cubic root of 666800839 is about 873.6390659698.

The spelling of 666800839 in words is "six hundred sixty-six million, eight hundred thousand, eight hundred thirty-nine".