127776661 has 4 divisors (see below), whose sum is σ = 133332192. Its totient is φ = 122221132.

The previous prime is 127776631. The next prime is 127776673. The reversal of 127776661 is 166677721.

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.

It is a cyclic number.

It is not a de Polignac number, because 127776661 - 2⁵ = 127776629 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 (127776611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2777731 + ... + 2777776.

It is an arithmetic number, because the mean of its divisors is an integer number (33333048).

Almost surely, 2^127776661 is an apocalyptic number.

It is an amenable number.

127776661 is a deficient number, since it is larger than the sum of its proper divisors (5555531).

127776661 is an equidigital number, since it uses as much as digits as its factorization.

127776661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5555530.

The product of its digits is 148176, while the sum is 43.

The square root of 127776661 is about 11303.8339071308. The cubic root of 127776661 is about 503.6751352437.

The spelling of 127776661 in words is "one hundred twenty-seven million, seven hundred seventy-six thousand, six hundred sixty-one".