2666131561 has 4 divisors (see below), whose sum is σ = 2698253712. Its totient is φ = 2634009412.

The previous prime is 2666131553. The next prime is 2666131577. The reversal of 2666131561 is 1651316662.

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 2666131561 - 2³ = 2666131553 is a prime.

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 2666131561.

It is not an unprimeable number, because it can be changed into a prime (2666131861) 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, 16060951 + ... + 16061116.

It is an arithmetic number, because the mean of its divisors is an integer number (674563428).

Almost surely, 2^2666131561 is an apocalyptic number.

It is an amenable number.

2666131561 is a deficient number, since it is larger than the sum of its proper divisors (32122151).

2666131561 is an equidigital number, since it uses as much as digits as its factorization.

2666131561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32122150.

The product of its digits is 38880, while the sum is 37.

The square root of 2666131561 is about 51634.5965511497. The cubic root of 2666131561 is about 1386.6297871096.

The spelling of 2666131561 in words is "two billion, six hundred sixty-six million, one hundred thirty-one thousand, five hundred sixty-one".