6663621 has 8 divisors (see below), whose sum is σ = 8905024. Its totient is φ = 4432320.

The previous prime is 6663617. The next prime is 6663647. The reversal of 6663621 is 1263666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6663621 - 2² = 6663617 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 (6663611) 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 7 ways as a sum of consecutive naturals, for example, 820 + ... + 3741.

It is an arithmetic number, because the mean of its divisors is an integer number (1113128).

Almost surely, 2^6663621 is an apocalyptic number.

It is an amenable number.

6663621 is a deficient number, since it is larger than the sum of its proper divisors (2241403).

6663621 is a wasteful number, since it uses less digits than its factorization.

6663621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5051.

The product of its digits is 7776, while the sum is 30.

The square root of 6663621 is about 2581.3990392808. The cubic root of 6663621 is about 188.1785405899.

The spelling of 6663621 in words is "six million, six hundred sixty-three thousand, six hundred twenty-one".