16921393 has 4 divisors (see below), whose sum is σ = 16935028. Its totient is φ = 16907760.

The previous prime is 16921391. The next prime is 16921427. The reversal of 16921393 is 39312961.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7969329 + 8952064 = 2823^2 + 2992^2 .

It is a cyclic number.

It is not a de Polignac number, because 16921393 - 2¹ = 16921391 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16921391) 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, 4746 + ... + 7507.

It is an arithmetic number, because the mean of its divisors is an integer number (4233757).

Almost surely, 2^16921393 is an apocalyptic number.

It is an amenable number.

16921393 is a deficient number, since it is larger than the sum of its proper divisors (13635).

16921393 is a wasteful number, since it uses less digits than its factorization.

16921393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13634.

The product of its digits is 8748, while the sum is 34.

The square root of 16921393 is about 4113.5620817000. The cubic root of 16921393 is about 256.7312314850.

The spelling of 16921393 in words is "sixteen million, nine hundred twenty-one thousand, three hundred ninety-three".