845280721 has 16 divisors (see below), whose sum is σ = 912788800. Its totient is φ = 780321600.

The previous prime is 845280701. The next prime is 845280757. The reversal of 845280721 is 127082548.

It is a cyclic number.

It is not a de Polignac number, because 845280721 - 2⁷ = 845280593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (845280701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 122986 + ... + 129676.

It is an arithmetic number, because the mean of its divisors is an integer number (57049300).

Almost surely, 2^845280721 is an apocalyptic number.

It is an amenable number.

845280721 is a deficient number, since it is larger than the sum of its proper divisors (67508079).

845280721 is a wasteful number, since it uses less digits than its factorization.

845280721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6880.

The product of its (nonzero) digits is 35840, while the sum is 37.

The square root of 845280721 is about 29073.7118545259. The cubic root of 845280721 is about 945.5118755723.

The spelling of 845280721 in words is "eight hundred forty-five million, two hundred eighty thousand, seven hundred twenty-one".