6407221 has 4 divisors (see below), whose sum is σ = 6413932. Its totient is φ = 6400512.

The previous prime is 6407209. The next prime is 6407227. The reversal of 6407221 is 1227046.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1227046 = 2 ⋅613523.

It can be written as a sum of positive squares in 2 ways, for example, as 5616900 + 790321 = 2370^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 6407221 - 2⁵ = 6407189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6407192 and 6407201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6407227) 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, 1626 + ... + 3931.

It is an arithmetic number, because the mean of its divisors is an integer number (1603483).

Almost surely, 2^6407221 is an apocalyptic number.

It is an amenable number.

6407221 is a deficient number, since it is larger than the sum of its proper divisors (6711).

6407221 is a wasteful number, since it uses less digits than its factorization.

6407221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6710.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 6407221 is about 2531.2489012343. The cubic root of 6407221 is about 185.7333540015.

The spelling of 6407221 in words is "six million, four hundred seven thousand, two hundred twenty-one".