16993909 has 4 divisors (see below), whose sum is σ = 17087980. Its totient is φ = 16899840.

The previous prime is 16993903. The next prime is 16993919. The reversal of 16993909 is 90939961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90939961 = 7 ⋅12991423.

It can be written as a sum of positive squares in 2 ways, for example, as 142884 + 16851025 = 378^2 + 4105^2 .

It is a cyclic number.

It is not a de Polignac number, because 16993909 - 2⁵ = 16993877 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 (16993903) 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, 46764 + ... + 47125.

It is an arithmetic number, because the mean of its divisors is an integer number (4271995).

Almost surely, 2^16993909 is an apocalyptic number.

It is an amenable number.

16993909 is a deficient number, since it is larger than the sum of its proper divisors (94071).

16993909 is an equidigital number, since it uses as much as digits as its factorization.

16993909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94070.

The product of its (nonzero) digits is 118098, while the sum is 46.

The square root of 16993909 is about 4122.3669171970. The cubic root of 16993909 is about 257.0974462285.

The spelling of 16993909 in words is "sixteen million, nine hundred ninety-three thousand, nine hundred nine".