6842395721 has 6 divisors (see below), whose sum is σ = 7959521610. Its totient is φ = 5864910576.

The previous prime is 6842395709. The next prime is 6842395751. The reversal of 6842395721 is 1275932486.

It can be written as a sum of positive squares in only one way, i.e., 3583698496 + 3258697225 = 59864^2 + 57085^2 .

It is not a de Polignac number, because 6842395721 - 2¹⁴ = 6842379337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6842395751) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 69820316 + ... + 69820413.

It is an arithmetic number, because the mean of its divisors is an integer number (1326586935).

Almost surely, 2^6842395721 is an apocalyptic number.

It is an amenable number.

6842395721 is a deficient number, since it is larger than the sum of its proper divisors (1117125889).

6842395721 is a wasteful number, since it uses less digits than its factorization.

6842395721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139640743 (or 139640736 counting only the distinct ones).

The product of its digits is 725760, while the sum is 47.

The square root of 6842395721 is about 82718.7749002607. The cubic root of 6842395721 is about 1898.4655867401.

The spelling of 6842395721 in words is "six billion, eight hundred forty-two million, three hundred ninety-five thousand, seven hundred twenty-one".