16809040 has 20 divisors (see below), whose sum is σ = 39081204. Its totient is φ = 6723584.

The previous prime is 16809031. The next prime is 16809043. The reversal of 16809040 is 4090861.

It can be written as a sum of positive squares in 2 ways, for example, as 10214416 + 6594624 = 3196^2 + 2568^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16809043) 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, 104977 + ... + 105136.

Almost surely, 2^16809040 is an apocalyptic number.

16809040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16809040 is an abundant number, since it is smaller than the sum of its proper divisors (22272164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16809040 is a wasteful number, since it uses less digits than its factorization.

16809040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210126 (or 210120 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 16809040 is about 4099.8829251577. The cubic root of 16809040 is about 256.1617629970.

The spelling of 16809040 in words is "sixteen million, eight hundred nine thousand, forty".