2805666681 has 4 divisors (see below), whose sum is σ = 3740888912. Its totient is φ = 1870444452.

The previous prime is 2805666667. The next prime is 2805666697. The reversal of 2805666681 is 1866665082.

It is a happy number.

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 not a de Polignac number, because 2805666681 - 2¹⁰ = 2805665657 is a prime.

It is a super-2 number, since 2×2805666681² = 15743531049747111522, which contains 22 as substring.

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 2805666681.

It is not an unprimeable number, because it can be changed into a prime (2805666641) 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, 467611111 + ... + 467611116.

It is an arithmetic number, because the mean of its divisors is an integer number (935222228).

Almost surely, 2^2805666681 is an apocalyptic number.

It is an amenable number.

2805666681 is a deficient number, since it is larger than the sum of its proper divisors (935222231).

2805666681 is an equidigital number, since it uses as much as digits as its factorization.

2805666681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935222230.

The product of its (nonzero) digits is 829440, while the sum is 48.

The square root of 2805666681 is about 52968.5442597774. The cubic root of 2805666681 is about 1410.4099341241.

The spelling of 2805666681 in words is "two billion, eight hundred five million, six hundred sixty-six thousand, six hundred eighty-one".