16821043 has 4 divisors (see below), whose sum is σ = 16856640. Its totient is φ = 16785448.

The previous prime is 16821019. The next prime is 16821071. The reversal of 16821043 is 34012861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34012861 = 101 ⋅336761.

It is a cyclic number.

It is not a de Polignac number, because 16821043 - 2⁵ = 16821011 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16820999 and 16821017.

It is not an unprimeable number, because it can be changed into a prime (16821083) 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, 17080 + ... + 18037.

It is an arithmetic number, because the mean of its divisors is an integer number (4214160).

Almost surely, 2^16821043 is an apocalyptic number.

16821043 is a deficient number, since it is larger than the sum of its proper divisors (35597).

16821043 is an equidigital number, since it uses as much as digits as its factorization.

16821043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35596.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 16821043 is about 4101.3464862164. The cubic root of 16821043 is about 256.2227218236. Note that the first 3 decimals are identical.

The spelling of 16821043 in words is "sixteen million, eight hundred twenty-one thousand, forty-three".