6671521 has 4 divisors (see below), whose sum is σ = 6697152. Its totient is φ = 6645892.

The previous prime is 6671519. The next prime is 6671549. The reversal of 6671521 is 1251766.

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: 1251766 = 2 ⋅625883.

It is a cyclic number.

It is not a de Polignac number, because 6671521 - 2¹ = 6671519 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 6671521.

It is not an unprimeable number, because it can be changed into a prime (6671501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12421 + ... + 12946.

It is an arithmetic number, because the mean of its divisors is an integer number (1674288).

Almost surely, 2^6671521 is an apocalyptic number.

It is an amenable number.

6671521 is a deficient number, since it is larger than the sum of its proper divisors (25631).

6671521 is a wasteful number, since it uses less digits than its factorization.

6671521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25630.

The product of its digits is 2520, while the sum is 28.

The square root of 6671521 is about 2582.9287640196. The cubic root of 6671521 is about 188.2528757188.

The spelling of 6671521 in words is "six million, six hundred seventy-one thousand, five hundred twenty-one".