127531661 has 4 divisors (see below), whose sum is σ = 127579452. Its totient is φ = 127483872.

The previous prime is 127531639. The next prime is 127531669. The reversal of 127531661 is 166135721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166135721 = 8543 ⋅19447.

It can be written as a sum of positive squares in 2 ways, for example, as 73788100 + 53743561 = 8590^2 + 7331^2 .

It is a cyclic number.

It is not a de Polignac number, because 127531661 - 2¹⁸ = 127269517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (127531669) 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 in 3 ways as a sum of consecutive naturals, for example, 19640 + ... + 25313.

It is an arithmetic number, because the mean of its divisors is an integer number (31894863).

Almost surely, 2^127531661 is an apocalyptic number.

It is an amenable number.

127531661 is a deficient number, since it is larger than the sum of its proper divisors (47791).

127531661 is an equidigital number, since it uses as much as digits as its factorization.

127531661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47790.

The product of its digits is 7560, while the sum is 32.

The square root of 127531661 is about 11292.9916762566. The cubic root of 127531661 is about 503.3530123538.

The spelling of 127531661 in words is "one hundred twenty-seven million, five hundred thirty-one thousand, six hundred sixty-one".