127716821 has 2 divisors, whose sum is σ = 127716822. Its totient is φ = 127716820.

The previous prime is 127716817. The next prime is 127716847. The reversal of 127716821 is 128617721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127012900 + 703921 = 11270^2 + 839^2 .

It is an emirp because it is prime and its reverse (128617721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 127716821 - 2² = 127716817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127716811) 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 as a sum of consecutive naturals, namely, 63858410 + 63858411.

It is an arithmetic number, because the mean of its divisors is an integer number (63858411).

Almost surely, 2^127716821 is an apocalyptic number.

It is an amenable number.

127716821 is a deficient number, since it is larger than the sum of its proper divisors (1).

127716821 is an equidigital number, since it uses as much as digits as its factorization.

127716821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9408, while the sum is 35.

The square root of 127716821 is about 11301.1867075985. The cubic root of 127716821 is about 503.5964964007.

The spelling of 127716821 in words is "one hundred twenty-seven million, seven hundred sixteen thousand, eight hundred twenty-one".