17421661 has 8 divisors (see below), whose sum is σ = 17911800. Its totient is φ = 16938240.

The previous prime is 17421647. The next prime is 17421671. The reversal of 17421661 is 16612471.

It can be written as a sum of positive squares in 4 ways, for example, as 32761 + 17388900 = 181^2 + 4170^2 .

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 17421661 - 2⁵ = 17421629 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 (17421611) 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, 3825 + ... + 7033.

It is an arithmetic number, because the mean of its divisors is an integer number (2238975).

Almost surely, 2^17421661 is an apocalyptic number.

It is an amenable number.

17421661 is a deficient number, since it is larger than the sum of its proper divisors (490139).

17421661 is an equidigital number, since it uses as much as digits as its factorization.

17421661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3359.

The product of its digits is 2016, while the sum is 28.

The square root of 17421661 is about 4173.9263290097. The cubic root of 17421661 is about 259.2367210095.

It can be divided in two parts, 1742 and 1661, that added together give a triangular number (3403 = T₈₂).

The spelling of 17421661 in words is "seventeen million, four hundred twenty-one thousand, six hundred sixty-one".