6421691 has 8 divisors (see below), whose sum is σ = 6538560. Its totient is φ = 6306048.

The previous prime is 6421643. The next prime is 6421697. The reversal of 6421691 is 1961246.

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 6421691 - 2¹⁸ = 6159547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6421697) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23045 + ... + 23321.

It is an arithmetic number, because the mean of its divisors is an integer number (817320).

Almost surely, 2^6421691 is an apocalyptic number.

6421691 is a deficient number, since it is larger than the sum of its proper divisors (116869).

6421691 is a wasteful number, since it uses less digits than its factorization.

6421691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 613.

The product of its digits is 2592, while the sum is 29.

The square root of 6421691 is about 2534.1055621264. The cubic root of 6421691 is about 185.8730682905.

The spelling of 6421691 in words is "six million, four hundred twenty-one thousand, six hundred ninety-one".