666827391 has 16 divisors (see below), whose sum is σ = 919930880. Its totient is φ = 429204960.

The previous prime is 666827377. The next prime is 666827419. The reversal of 666827391 is 193728666.

It is not a de Polignac number, because 666827391 - 2⁶ = 666827327 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 666827391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666827191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32661 + ... + 48993.

It is an arithmetic number, because the mean of its divisors is an integer number (57495680).

Almost surely, 2^666827391 is an apocalyptic number.

666827391 is a deficient number, since it is larger than the sum of its proper divisors (253103489).

666827391 is a wasteful number, since it uses less digits than its factorization.

666827391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16806.

The product of its digits is 653184, while the sum is 48.

The square root of 666827391 is about 25823.0012004802. The cubic root of 666827391 is about 873.6506619143.

The spelling of 666827391 in words is "six hundred sixty-six million, eight hundred twenty-seven thousand, three hundred ninety-one".