16940921 has 4 divisors (see below), whose sum is σ = 16986000. Its totient is φ = 16895844.

The previous prime is 16940909. The next prime is 16940923. The reversal of 16940921 is 12904961.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16940921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16940923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21971 + ... + 22728.

It is an arithmetic number, because the mean of its divisors is an integer number (4246500).

Almost surely, 2^16940921 is an apocalyptic number.

It is an amenable number.

16940921 is a deficient number, since it is larger than the sum of its proper divisors (45079).

16940921 is an equidigital number, since it uses as much as digits as its factorization.

16940921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45078.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 16940921 is about 4115.9350092051. The cubic root of 16940921 is about 256.8299530687.

The spelling of 16940921 in words is "sixteen million, nine hundred forty thousand, nine hundred twenty-one".