8544437721 has 12 divisors (see below), whose sum is σ = 12387850020. Its totient is φ = 5675114400.

The previous prime is 8544437717. The next prime is 8544437723. The reversal of 8544437721 is 1277344458.

8544437721 is a `hidden beast` number, since 8 + 544 + 4 + 37 + 72 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4350062025 + 4194375696 = 65955^2 + 64764^2 .

It is not a de Polignac number, because 8544437721 - 2² = 8544437717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8544437723) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1762230 + ... + 1767071.

It is an arithmetic number, because the mean of its divisors is an integer number (1032320835).

Almost surely, 2^8544437721 is an apocalyptic number.

It is an amenable number.

8544437721 is a deficient number, since it is larger than the sum of its proper divisors (3843412299).

8544437721 is a wasteful number, since it uses less digits than its factorization.

8544437721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3529576 (or 3529573 counting only the distinct ones).

The product of its digits is 752640, while the sum is 45.

The square root of 8544437721 is about 92436.1277910320. The cubic root of 8544437721 is about 2044.3778310282.

The spelling of 8544437721 in words is "eight billion, five hundred forty-four million, four hundred thirty-seven thousand, seven hundred twenty-one".