16172321 has 16 divisors (see below), whose sum is σ = 18817920. Its totient is φ = 13735680.

The previous prime is 16172263. The next prime is 16172353. The reversal of 16172321 is 12327161.

16172321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 16172321 - 2¹⁰ = 16171297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16172521) 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, 36620 + ... + 37058.

It is an arithmetic number, because the mean of its divisors is an integer number (1176120).

Almost surely, 2^16172321 is an apocalyptic number.

16172321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16172321 is a deficient number, since it is larger than the sum of its proper divisors (2645599).

16172321 is a wasteful number, since it uses less digits than its factorization.

16172321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664.

The product of its digits is 504, while the sum is 23.

The square root of 16172321 is about 4021.4824381066. The cubic root of 16172321 is about 252.8856102005.

Adding to 16172321 its reverse (12327161), we get a palindrome (28499482).

The spelling of 16172321 in words is "sixteen million, one hundred seventy-two thousand, three hundred twenty-one".