6416821 has 4 divisors (see below), whose sum is σ = 6456352. Its totient is φ = 6377292.

The previous prime is 6416819. The next prime is 6416827. The reversal of 6416821 is 1286146.

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: 1286146 = 2 ⋅643073.

It is a 4-Lehmer number, since φ(6416821) divides (6416821-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 6416821 - 2¹ = 6416819 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6416821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6416827) 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, 19521 + ... + 19846.

It is an arithmetic number, because the mean of its divisors is an integer number (1614088).

Almost surely, 2^6416821 is an apocalyptic number.

It is an amenable number.

6416821 is a deficient number, since it is larger than the sum of its proper divisors (39531).

6416821 is a wasteful number, since it uses less digits than its factorization.

6416821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39530.

The product of its digits is 2304, while the sum is 28.

The square root of 6416821 is about 2533.1444885754. The cubic root of 6416821 is about 185.8260697267.

The spelling of 6416821 in words is "six million, four hundred sixteen thousand, eight hundred twenty-one".