2805918721 has 4 divisors (see below), whose sum is σ = 2807373744. Its totient is φ = 2804463700.

The previous prime is 2805918719. The next prime is 2805918757. The reversal of 2805918721 is 1278195082.

It is a happy number.

2805918721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2805918721 - 2¹ = 2805918719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2805918781) 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, 724615 + ... + 728476.

It is an arithmetic number, because the mean of its divisors is an integer number (701843436).

Almost surely, 2^2805918721 is an apocalyptic number.

It is an amenable number.

2805918721 is a deficient number, since it is larger than the sum of its proper divisors (1455023).

2805918721 is a wasteful number, since it uses less digits than its factorization.

2805918721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1455022.

The product of its (nonzero) digits is 80640, while the sum is 43.

The square root of 2805918721 is about 52970.9233542327. The cubic root of 2805918721 is about 1410.4521664010.

The spelling of 2805918721 in words is "two billion, eight hundred five million, nine hundred eighteen thousand, seven hundred twenty-one".