6821406 has 12 divisors (see below), whose sum is σ = 14779752. Its totient is φ = 2273796.

The previous prime is 6821401. The next prime is 6821407. The reversal of 6821406 is 6041286.

It is a self number, because there is not a number n which added to its sum of digits gives 6821406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6821401) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 189466 + ... + 189501.

It is an arithmetic number, because the mean of its divisors is an integer number (1231646).

Almost surely, 2^6821406 is an apocalyptic number.

6821406 is an abundant number, since it is smaller than the sum of its proper divisors (7958346).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6821406 is a wasteful number, since it uses less digits than its factorization.

6821406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378975 (or 378972 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 6821406 is about 2611.7821501802. The cubic root of 6821406 is about 189.6522355141.

It can be divided in two parts, 6821 and 406, that added together give a palindrome (7227).

The spelling of 6821406 in words is "six million, eight hundred twenty-one thousand, four hundred six".