6669621 has 28 divisors (see below), whose sum is σ = 11437152. Its totient is φ = 3808296.

The previous prime is 6669617. The next prime is 6669643. The reversal of 6669621 is 1269666.

It is a happy number.

It is not a de Polignac number, because 6669621 - 2² = 6669617 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

6669621 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6669671) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 4450 + ... + 5756.

Almost surely, 2^6669621 is an apocalyptic number.

It is an amenable number.

6669621 is a deficient number, since it is larger than the sum of its proper divisors (4767531).

6669621 is an equidigital number, since it uses as much as digits as its factorization.

6669621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332 (or 1317 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 6669621 is about 2582.5609382936. The cubic root of 6669621 is about 188.2350030116.

The spelling of 6669621 in words is "six million, six hundred sixty-nine thousand, six hundred twenty-one".