127705681 has 4 divisors (see below), whose sum is σ = 127728292. Its totient is φ = 127683072.

The previous prime is 127705667. The next prime is 127705687. The reversal of 127705681 is 186507721.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 186507721 = 1873 ⋅99577.

It can be written as a sum of positive squares in 2 ways, for example, as 31979025 + 95726656 = 5655^2 + 9784^2 .

It is a cyclic number.

It is not a de Polignac number, because 127705681 - 2⁹ = 127705169 is a prime.

It is a super-2 number, since 2×127705681² = 32617481919347522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 127705681.

It is not an unprimeable number, because it can be changed into a prime (127705687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5185 + ... + 16801.

It is an arithmetic number, because the mean of its divisors is an integer number (31932073).

Almost surely, 2^127705681 is an apocalyptic number.

It is an amenable number.

127705681 is a deficient number, since it is larger than the sum of its proper divisors (22611).

127705681 is a wasteful number, since it uses less digits than its factorization.

127705681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22610.

The product of its (nonzero) digits is 23520, while the sum is 37.

The square root of 127705681 is about 11300.6938282567. The cubic root of 127705681 is about 503.5818540379.

The spelling of 127705681 in words is "one hundred twenty-seven million, seven hundred five thousand, six hundred eighty-one".