16981309 has 4 divisors (see below), whose sum is σ = 17093920. Its totient is φ = 16868700.

The previous prime is 16981303. The next prime is 16981313. The reversal of 16981309 is 90318961.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90318961 = 37 ⋅2441053.

It is a cyclic number.

It is not a de Polignac number, because 16981309 - 2⁹ = 16980797 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 (16981303) 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, 56079 + ... + 56380.

It is an arithmetic number, because the mean of its divisors is an integer number (4273480).

Almost surely, 2^16981309 is an apocalyptic number.

It is an amenable number.

16981309 is a deficient number, since it is larger than the sum of its proper divisors (112611).

16981309 is a wasteful number, since it uses less digits than its factorization.

16981309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112610.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 16981309 is about 4120.8383855716. The cubic root of 16981309 is about 257.0338895591.

The spelling of 16981309 in words is "sixteen million, nine hundred eighty-one thousand, three hundred nine".