16945921 has 4 divisors (see below), whose sum is σ = 17233200. Its totient is φ = 16658644.

The previous prime is 16945909. The next prime is 16945927. The reversal of 16945921 is 12954961.

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 not a de Polignac number, because 16945921 - 2⁷ = 16945793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16945927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 143551 + ... + 143668.

It is an arithmetic number, because the mean of its divisors is an integer number (4308300).

Almost surely, 2^16945921 is an apocalyptic number.

It is an amenable number.

16945921 is a deficient number, since it is larger than the sum of its proper divisors (287279).

16945921 is an equidigital number, since it uses as much as digits as its factorization.

16945921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287278.

The product of its digits is 19440, while the sum is 37.

The square root of 16945921 is about 4116.5423597966. The cubic root of 16945921 is about 256.8552178000.

The spelling of 16945921 in words is "sixteen million, nine hundred forty-five thousand, nine hundred twenty-one".