6421660621 has 8 divisors (see below), whose sum is σ = 6473023200. Its totient is φ = 6370470480.

The previous prime is 6421660613. The next prime is 6421660649. The reversal of 6421660621 is 1260661246.

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

It is a cyclic number.

It is not a de Polignac number, because 6421660621 - 2³ = 6421660613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6421660681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32191 + ... + 117811.

It is an arithmetic number, because the mean of its divisors is an integer number (809127900).

Almost surely, 2^6421660621 is an apocalyptic number.

It is an amenable number.

6421660621 is a deficient number, since it is larger than the sum of its proper divisors (51362579).

6421660621 is a wasteful number, since it uses less digits than its factorization.

6421660621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86219.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 6421660621 is about 80135.2645281714. The cubic root of 6421660621 is about 1858.7277518775.

The spelling of 6421660621 in words is "six billion, four hundred twenty-one million, six hundred sixty thousand, six hundred twenty-one".