666127821 has 8 divisors (see below), whose sum is σ = 934916320. Its totient is φ = 420712272.

The previous prime is 666127811. The next prime is 666127831. The reversal of 666127821 is 128721666.

It is an interprime number because it is at equal distance from previous prime (666127811) and next prime (666127831).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 666127821 - 2⁵ = 666127789 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 666127821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666127811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5843170 + ... + 5843283.

It is an arithmetic number, because the mean of its divisors is an integer number (116864540).

Almost surely, 2^666127821 is an apocalyptic number.

It is an amenable number.

666127821 is a deficient number, since it is larger than the sum of its proper divisors (268788499).

666127821 is a wasteful number, since it uses less digits than its factorization.

666127821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11686475.

The product of its digits is 48384, while the sum is 39.

The square root of 666127821 is about 25809.4521638876. The cubic root of 666127821 is about 873.3450387718.

The spelling of 666127821 in words is "six hundred sixty-six million, one hundred twenty-seven thousand, eight hundred twenty-one".