328401642721 has 4 divisors (see below), whose sum is σ = 328409873812. Its totient is φ = 328393411632.

The previous prime is 328401642719. The next prime is 328401642763. The reversal of 328401642721 is 127246104823.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127246104823 = 3659 ⋅34776197.

It can be written as a sum of positive squares in 2 ways, for example, as 165095942400 + 163305700321 = 406320^2 + 404111^2 .

It is a cyclic number.

It is not a de Polignac number, because 328401642721 - 2¹ = 328401642719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (328401042721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4055406 + ... + 4135591.

It is an arithmetic number, because the mean of its divisors is an integer number (82102468453).

Almost surely, 2^328401642721 is an apocalyptic number.

It is an amenable number.

328401642721 is a deficient number, since it is larger than the sum of its proper divisors (8231091).

328401642721 is an equidigital number, since it uses as much as digits as its factorization.

328401642721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8231090.

The product of its (nonzero) digits is 129024, while the sum is 40.

The spelling of 328401642721 in words is "three hundred twenty-eight billion, four hundred one million, six hundred forty-two thousand, seven hundred twenty-one".