17940921 has 16 divisors (see below), whose sum is σ = 25347840. Its totient is φ = 11255760.

The previous prime is 17940917. The next prime is 17940931. The reversal of 17940921 is 12904971.

It is not a de Polignac number, because 17940921 - 2² = 17940917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (17940931) 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 15 ways as a sum of consecutive naturals, for example, 8326 + ... + 10256.

It is an arithmetic number, because the mean of its divisors is an integer number (1584240).

Almost surely, 2^17940921 is an apocalyptic number.

It is an amenable number.

17940921 is a deficient number, since it is larger than the sum of its proper divisors (7406919).

17940921 is a wasteful number, since it uses less digits than its factorization.

17940921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2116.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 17940921 is about 4235.6724377600. The cubic root of 17940921 is about 261.7871014878.

The spelling of 17940921 in words is "seventeen million, nine hundred forty thousand, nine hundred twenty-one".