6621091 has 4 divisors (see below), whose sum is σ = 6647112. Its totient is φ = 6595072.

The previous prime is 6621071. The next prime is 6621103. The reversal of 6621091 is 1901266.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1901266 = 2 ⋅950633.

It is a cyclic number.

It is not a de Polignac number, because 6621091 - 2¹¹ = 6619043 is a prime.

It is a Duffinian number.

6621091 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6621061) 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, 12625 + ... + 13138.

It is an arithmetic number, because the mean of its divisors is an integer number (1661778).

Almost surely, 2^6621091 is an apocalyptic number.

6621091 is a deficient number, since it is larger than the sum of its proper divisors (26021).

6621091 is a wasteful number, since it uses less digits than its factorization.

6621091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26020.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 6621091 is about 2573.1480719150. The cubic root of 6621091 is about 187.7773412711. Note that the first 3 decimals are identical.

The spelling of 6621091 in words is "six million, six hundred twenty-one thousand, ninety-one".