127959691661 has 2 divisors, whose sum is σ = 127959691662. Its totient is φ = 127959691660.

The previous prime is 127959691633. The next prime is 127959691729. The reversal of 127959691661 is 166196959721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93716189161 + 34243502500 = 306131^2 + 185050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-127959691661 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 127959691594 and 127959691603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127959691261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63979845830 + 63979845831.

It is an arithmetic number, because the mean of its divisors is an integer number (63979845831).

Almost surely, 2^127959691661 is an apocalyptic number.

It is an amenable number.

127959691661 is a deficient number, since it is larger than the sum of its proper divisors (1).

127959691661 is an equidigital number, since it uses as much as digits as its factorization.

127959691661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11022480, while the sum is 62.

The spelling of 127959691661 in words is "one hundred twenty-seven billion, nine hundred fifty-nine million, six hundred ninety-one thousand, six hundred sixty-one".