8358445721 has 4 divisors (see below), whose sum is σ = 8367367092. Its totient is φ = 8349524352.

The previous prime is 8358445681. The next prime is 8358445759. The reversal of 8358445721 is 1275448538.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 192793225 + 8165652496 = 13885^2 + 90364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8358445721 is a prime.

It is a super-2 number, since 2×8358445721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8358445621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4459280 + ... + 4461153.

It is an arithmetic number, because the mean of its divisors is an integer number (2091841773).

Almost surely, 2^8358445721 is an apocalyptic number.

It is an amenable number.

8358445721 is a deficient number, since it is larger than the sum of its proper divisors (8921371).

8358445721 is an equidigital number, since it uses as much as digits as its factorization.

8358445721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8921370.

The product of its digits is 1075200, while the sum is 47.

The square root of 8358445721 is about 91424.5356619327. The cubic root of 8358445721 is about 2029.4351377974.

The spelling of 8358445721 in words is "eight billion, three hundred fifty-eight million, four hundred forty-five thousand, seven hundred twenty-one".