127591661 has 2 divisors, whose sum is σ = 127591662. Its totient is φ = 127591660.

The previous prime is 127591657. The next prime is 127591729. The reversal of 127591661 is 166195721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 113827561 + 13764100 = 10669^2 + 3710^2 .

It is an emirp because it is prime and its reverse (166195721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 127591661 - 2² = 127591657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127591601) 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, 63795830 + 63795831.

It is an arithmetic number, because the mean of its divisors is an integer number (63795831).

Almost surely, 2^127591661 is an apocalyptic number.

It is an amenable number.

127591661 is a deficient number, since it is larger than the sum of its proper divisors (1).

127591661 is an equidigital number, since it uses as much as digits as its factorization.

127591661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 38.

The square root of 127591661 is about 11295.6478787186. The cubic root of 127591661 is about 503.4319377110.

The spelling of 127591661 in words is "one hundred twenty-seven million, five hundred ninety-one thousand, six hundred sixty-one".