16800421 has 4 divisors (see below), whose sum is σ = 18327744. Its totient is φ = 15273100.

The previous prime is 16800409. The next prime is 16800431. The reversal of 16800421 is 12400861.

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: 12400861 = 11 ⋅1127351.

It is a cyclic number.

It is not a de Polignac number, because 16800421 - 2¹³ = 16792229 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16800392 and 16800401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16800431) 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, 763645 + ... + 763666.

It is an arithmetic number, because the mean of its divisors is an integer number (4581936).

Almost surely, 2^16800421 is an apocalyptic number.

16800421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16800421 is a deficient number, since it is larger than the sum of its proper divisors (1527323).

16800421 is a wasteful number, since it uses less digits than its factorization.

16800421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1527322.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 16800421 is about 4098.8316628034. The cubic root of 16800421 is about 256.1179723599.

The spelling of 16800421 in words is "sixteen million, eight hundred thousand, four hundred twenty-one".