16340021 has 4 divisors (see below), whose sum is σ = 16903500. Its totient is φ = 15776544.

The previous prime is 16340003. The next prime is 16340033. The reversal of 16340021 is 12004361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12004361 = 521 ⋅23041.

It can be written as a sum of positive squares in 2 ways, for example, as 5522500 + 10817521 = 2350^2 + 3289^2 .

It is a cyclic number.

It is not a de Polignac number, because 16340021 - 2¹⁰ = 16338997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16340221) 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 3 ways as a sum of consecutive naturals, for example, 281696 + ... + 281753.

It is an arithmetic number, because the mean of its divisors is an integer number (4225875).

Almost surely, 2^16340021 is an apocalyptic number.

It is an amenable number.

16340021 is a deficient number, since it is larger than the sum of its proper divisors (563479).

16340021 is an equidigital number, since it uses as much as digits as its factorization.

16340021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563478.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 16340021 is about 4042.2791838269. The cubic root of 16340021 is about 253.7567110587.

Adding to 16340021 its reverse (12004361), we get a palindrome (28344382).

The spelling of 16340021 in words is "sixteen million, three hundred forty thousand, twenty-one".