844541721 has 15 divisors (see below), whose sum is σ = 1261990191. Its totient is φ = 562853448.

The previous prime is 844541707. The next prime is 844541723. The reversal of 844541721 is 127145448.

It is a happy number.

The square root of 844541721 is 29061.

It is a perfect power (a square), and thus also a powerful number.

844541721 is a `hidden beast` number, since 8 + 44 + 541 + 72 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 254051721 + 590490000 = 15939^2 + 24300^2 .

It is not a de Polignac number, because 844541721 - 2¹⁵ = 844508953 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (844541723) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 259935 + ... + 263163.

Almost surely, 2^844541721 is an apocalyptic number.

844541721 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

844541721 is the 29061-st square number.

844541721 is the 14531-st centered octagonal number.

It is an amenable number.

844541721 is a deficient number, since it is larger than the sum of its proper divisors (417448470).

844541721 is an frugal number, since it uses more digits than its factorization.

844541721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6470 (or 3232 counting only the distinct ones).

The product of its digits is 35840, while the sum is 36.

The cubic root of 844541721 is about 945.2362523449.

Multiplying 844541721 by its sum of digits (36), we get a square (30403501956 = 174366²).

The spelling of 844541721 in words is "eight hundred forty-four million, five hundred forty-one thousand, seven hundred twenty-one".