127555561 has 4 divisors (see below), whose sum is σ = 145777792. Its totient is φ = 109333332.

The previous prime is 127555559. The next prime is 127555567. The reversal of 127555561 is 165555721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165555721 = 19 ⋅8713459.

It is a cyclic number.

It is not a de Polignac number, because 127555561 - 2¹ = 127555559 is a prime.

It is a super-2 number, since 2×127555561² = 32540842284049442, 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 127555561.

It is not an unprimeable number, because it can be changed into a prime (127555567) 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, 9111105 + ... + 9111118.

It is an arithmetic number, because the mean of its divisors is an integer number (36444448).

Almost surely, 2^127555561 is an apocalyptic number.

It is an amenable number.

127555561 is a deficient number, since it is larger than the sum of its proper divisors (18222231).

127555561 is an equidigital number, since it uses as much as digits as its factorization.

127555561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18222230.

The product of its digits is 52500, while the sum is 37.

The square root of 127555561 is about 11294.0498050965. The cubic root of 127555561 is about 503.3844539202.

The spelling of 127555561 in words is "one hundred twenty-seven million, five hundred fifty-five thousand, five hundred sixty-one".