16401321 has 12 divisors (see below), whose sum is σ = 23744448. Its totient is φ = 10909464.

The previous prime is 16401317. The next prime is 16401337. The reversal of 16401321 is 12310461.

It is a happy number.

16401321 is a `hidden beast` number, since 1 + 640 + 1 + 3 + 21 = 666.

It is not a de Polignac number, because 16401321 - 2² = 16401317 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16401294 and 16401303.

It is not an unprimeable number, because it can be changed into a prime (16401391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2716 + ... + 6338.

It is an arithmetic number, because the mean of its divisors is an integer number (1978704).

Almost surely, 2^16401321 is an apocalyptic number.

It is an amenable number.

16401321 is a deficient number, since it is larger than the sum of its proper divisors (7343127).

16401321 is a wasteful number, since it uses less digits than its factorization.

16401321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4132 (or 4129 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 16401321 is about 4049.8544418287. The cubic root of 16401321 is about 254.0736399621.

Adding to 16401321 its reverse (12310461), we get a palindrome (28711782).

The spelling of 16401321 in words is "sixteen million, four hundred one thousand, three hundred twenty-one".