127212775561 has 9 divisors (see below), whose sum is σ = 128572734549. Its totient is φ = 125867063424.

The previous prime is 127212775523. The next prime is 127212775567. The reversal of 127212775561 is 165577212721.

The square root of 127212775561 is 356669.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 8945565561 + 118267210000 = 94581^2 + 343900^2 .

It is not a de Polignac number, because 127212775561 - 2⁹ = 127212775049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (127212775567) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 34595055 + ... + 34598731.

Almost surely, 2^127212775561 is an apocalyptic number.

127212775561 is the 356669-th square number.

127212775561 is the 178335-th centered octagonal number.

It is an amenable number.

127212775561 is a deficient number, since it is larger than the sum of its proper divisors (1359958988).

127212775561 is an frugal number, since it uses more digits than its factorization.

127212775561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7548 (or 3774 counting only the distinct ones).

The product of its digits is 411600, while the sum is 46.

The spelling of 127212775561 in words is "one hundred twenty-seven billion, two hundred twelve million, seven hundred seventy-five thousand, five hundred sixty-one".