16842421 has 2 divisors, whose sum is σ = 16842422. Its totient is φ = 16842420.

The previous prime is 16842361. The next prime is 16842433. The reversal of 16842421 is 12424861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16719921 + 122500 = 4089^2 + 350^2 .

It is an emirp because it is prime and its reverse (12424861) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16842421 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16842421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16842481) 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 as a sum of consecutive naturals, namely, 8421210 + 8421211.

It is an arithmetic number, because the mean of its divisors is an integer number (8421211).

Almost surely, 2^16842421 is an apocalyptic number.

It is an amenable number.

16842421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16842421 is an equidigital number, since it uses as much as digits as its factorization.

16842421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3072, while the sum is 28.

The square root of 16842421 is about 4103.9518759362. The cubic root of 16842421 is about 256.3312210510.

The spelling of 16842421 in words is "sixteen million, eight hundred forty-two thousand, four hundred twenty-one".