16307221 has 4 divisors (see below), whose sum is σ = 18636832. Its totient is φ = 13977612.

The previous prime is 16307201. The next prime is 16307227. The reversal of 16307221 is 12270361.

16307221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12270361 = 193 ⋅63577.

It is a cyclic number.

It is not a de Polignac number, because 16307221 - 2¹⁹ = 15782933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16307192 and 16307201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16307227) 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, 1164795 + ... + 1164808.

It is an arithmetic number, because the mean of its divisors is an integer number (4659208).

Almost surely, 2^16307221 is an apocalyptic number.

It is an amenable number.

16307221 is a deficient number, since it is larger than the sum of its proper divisors (2329611).

16307221 is an equidigital number, since it uses as much as digits as its factorization.

16307221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2329610.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 16307221 is about 4038.2200286760. The cubic root of 16307221 is about 253.5868052077.

Adding to 16307221 its reverse (12270361), we get a palindrome (28577582).

The spelling of 16307221 in words is "sixteen million, three hundred seven thousand, two hundred twenty-one".