127664821 has 2 divisors, whose sum is σ = 127664822. Its totient is φ = 127664820.

The previous prime is 127664813. The next prime is 127664843. The reversal of 127664821 is 128466721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 94187025 + 33477796 = 9705^2 + 5786^2 .

It is an emirp because it is prime and its reverse (128466721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 127664821 - 2³ = 127664813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127664891) 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 as a sum of consecutive naturals, namely, 63832410 + 63832411.

It is an arithmetic number, because the mean of its divisors is an integer number (63832411).

Almost surely, 2^127664821 is an apocalyptic number.

It is an amenable number.

127664821 is a deficient number, since it is larger than the sum of its proper divisors (1).

127664821 is an equidigital number, since it uses as much as digits as its factorization.

127664821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 37.

The square root of 127664821 is about 11298.8858300277. The cubic root of 127664821 is about 503.5281405584.

The spelling of 127664821 in words is "one hundred twenty-seven million, six hundred sixty-four thousand, eight hundred twenty-one".