2271666561 has 4 divisors (see below), whose sum is σ = 3028888752. Its totient is φ = 1514444372.

The previous prime is 2271666539. The next prime is 2271666569. The reversal of 2271666561 is 1656661722.

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 2271666561 - 2¹³ = 2271658369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2271666569) 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, 378611091 + ... + 378611096.

It is an arithmetic number, because the mean of its divisors is an integer number (757222188).

Almost surely, 2^2271666561 is an apocalyptic number.

It is an amenable number.

2271666561 is a deficient number, since it is larger than the sum of its proper divisors (757222191).

2271666561 is an equidigital number, since it uses as much as digits as its factorization.

2271666561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757222190.

The product of its digits is 181440, while the sum is 42.

The square root of 2271666561 is about 47662.0033255003. The cubic root of 2271666561 is about 1314.5633755015.

The spelling of 2271666561 in words is "two billion, two hundred seventy-one million, six hundred sixty-six thousand, five hundred sixty-one".