16221937 has 4 divisors (see below), whose sum is σ = 16617636. Its totient is φ = 15826240.

The previous prime is 16221929. The next prime is 16221971. The reversal of 16221937 is 73912261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73912261 = 19 ⋅3890119.

It can be written as a sum of positive squares in 2 ways, for example, as 9790641 + 6431296 = 3129^2 + 2536^2 .

It is a cyclic number.

It is not a de Polignac number, because 16221937 - 2³ = 16221929 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16221899 and 16221908.

It is not an unprimeable number, because it can be changed into a prime (16221917) 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, 197788 + ... + 197869.

It is an arithmetic number, because the mean of its divisors is an integer number (4154409).

Almost surely, 2^16221937 is an apocalyptic number.

It is an amenable number.

16221937 is a deficient number, since it is larger than the sum of its proper divisors (395699).

16221937 is an equidigital number, since it uses as much as digits as its factorization.

16221937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395698.

The product of its digits is 4536, while the sum is 31.

The square root of 16221937 is about 4027.6465833040. The cubic root of 16221937 is about 253.1439603132.

The spelling of 16221937 in words is "sixteen million, two hundred twenty-one thousand, nine hundred thirty-seven".