328669721 has 16 divisors (see below), whose sum is σ = 354430080. Its totient is φ = 303663360.

The previous prime is 328669711. The next prime is 328669723. The reversal of 328669721 is 127966823.

It is a cyclic number.

It is not a de Polignac number, because 328669721 - 2¹⁴ = 328653337 is a prime.

It is a super-3 number, since 3×328669721³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (328669723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 382190 + ... + 383048.

It is an arithmetic number, because the mean of its divisors is an integer number (22151880).

Almost surely, 2^328669721 is an apocalyptic number.

It is an amenable number.

328669721 is a deficient number, since it is larger than the sum of its proper divisors (25760359).

328669721 is a wasteful number, since it uses less digits than its factorization.

328669721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1264.

The product of its digits is 217728, while the sum is 44.

The square root of 328669721 is about 18129.2504257622. The cubic root of 328669721 is about 690.1125077340.

The spelling of 328669721 in words is "three hundred twenty-eight million, six hundred sixty-nine thousand, seven hundred twenty-one".