6667421 has 4 divisors (see below), whose sum is σ = 6728700. Its totient is φ = 6606144.

The previous prime is 6667403. The next prime is 6667429. The reversal of 6667421 is 1247666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3463321 + 3204100 = 1861^2 + 1790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6667421 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6667429) 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, 30476 + ... + 30693.

It is an arithmetic number, because the mean of its divisors is an integer number (1682175).

Almost surely, 2^6667421 is an apocalyptic number.

It is an amenable number.

6667421 is a deficient number, since it is larger than the sum of its proper divisors (61279).

6667421 is a wasteful number, since it uses less digits than its factorization.

6667421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61278.

The product of its digits is 12096, while the sum is 32.

The square root of 6667421 is about 2582.1349693616. The cubic root of 6667421 is about 188.2143040569.

The spelling of 6667421 in words is "six million, six hundred sixty-seven thousand, four hundred twenty-one".