127765681 has 2 divisors, whose sum is σ = 127765682. Its totient is φ = 127765680.

The previous prime is 127765657. The next prime is 127765691. The reversal of 127765681 is 186567721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113635600 + 14130081 = 10660^2 + 3759^2 .

It is an emirp because it is prime and its reverse (186567721) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-127765681 is a prime.

It is a super-2 number, since 2×127765681² = 32648138482787522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (127765691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63882840 + 63882841.

It is an arithmetic number, because the mean of its divisors is an integer number (63882841).

Almost surely, 2^127765681 is an apocalyptic number.

It is an amenable number.

127765681 is a deficient number, since it is larger than the sum of its proper divisors (1).

127765681 is an equidigital number, since it uses as much as digits as its factorization.

127765681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 43.

The square root of 127765681 is about 11303.3482207707. The cubic root of 127765681 is about 503.6607076965.

The spelling of 127765681 in words is "one hundred twenty-seven million, seven hundred sixty-five thousand, six hundred eighty-one".