16981509 has 4 divisors (see below), whose sum is σ = 22642016. Its totient is φ = 11321004.

The previous prime is 16981493. The next prime is 16981511. The reversal of 16981509 is 90518961.

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 not a de Polignac number, because 16981509 - 2⁴ = 16981493 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 (16981009) 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, 2830249 + ... + 2830254.

It is an arithmetic number, because the mean of its divisors is an integer number (5660504).

Almost surely, 2^16981509 is an apocalyptic number.

It is an amenable number.

16981509 is a deficient number, since it is larger than the sum of its proper divisors (5660507).

16981509 is an equidigital number, since it uses as much as digits as its factorization.

16981509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5660506.

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 16981509 is about 4120.8626524067. The cubic root of 16981509 is about 257.0348986406.

The spelling of 16981509 in words is "sixteen million, nine hundred eighty-one thousand, five hundred nine".