2661813871 has 4 divisors (see below), whose sum is σ = 2663058112. Its totient is φ = 2660569632.

The previous prime is 2661813863. The next prime is 2661813991. The reversal of 2661813871 is 1783181662.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2661813871 - 2³ = 2661813863 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 (2661813841) 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, 618906 + ... + 623191.

It is an arithmetic number, because the mean of its divisors is an integer number (665764528).

Almost surely, 2^2661813871 is an apocalyptic number.

2661813871 is a deficient number, since it is larger than the sum of its proper divisors (1244241).

2661813871 is a wasteful number, since it uses less digits than its factorization.

2661813871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1244240.

The product of its digits is 96768, while the sum is 43.

The square root of 2661813871 is about 51592.7695612476. The cubic root of 2661813871 is about 1385.8808527754.

The spelling of 2661813871 in words is "two billion, six hundred sixty-one million, eight hundred thirteen thousand, eight hundred seventy-one".