127989661 has 2 divisors, whose sum is σ = 127989662. Its totient is φ = 127989660.

The previous prime is 127989613. The next prime is 127989679. The reversal of 127989661 is 166989721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127825636 + 164025 = 11306^2 + 405^2 .

It is a cyclic number.

It is not a de Polignac number, because 127989661 - 2¹⁷ = 127858589 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127989611) 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, 63994830 + 63994831.

It is an arithmetic number, because the mean of its divisors is an integer number (63994831).

Almost surely, 2^127989661 is an apocalyptic number.

It is an amenable number.

127989661 is a deficient number, since it is larger than the sum of its proper divisors (1).

127989661 is an equidigital number, since it uses as much as digits as its factorization.

127989661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 49.

The square root of 127989661 is about 11313.2515661944. The cubic root of 127989661 is about 503.9548505054.

The spelling of 127989661 in words is "one hundred twenty-seven million, nine hundred eighty-nine thousand, six hundred sixty-one".