16550509 has 2 divisors, whose sum is σ = 16550510. Its totient is φ = 16550508.

The previous prime is 16550491. The next prime is 16550549. The reversal of 16550509 is 90505561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12638025 + 3912484 = 3555^2 + 1978^2 .

It is an emirp because it is prime and its reverse (90505561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16550509 - 2⁵ = 16550477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16550549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8275254 + 8275255.

It is an arithmetic number, because the mean of its divisors is an integer number (8275255).

Almost surely, 2^16550509 is an apocalyptic number.

It is an amenable number.

16550509 is a deficient number, since it is larger than the sum of its proper divisors (1).

16550509 is an equidigital number, since it uses as much as digits as its factorization.

16550509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6750, while the sum is 31.

The square root of 16550509 is about 4068.2316797351. The cubic root of 16550509 is about 254.8416753964.

The spelling of 16550509 in words is "sixteen million, five hundred fifty thousand, five hundred nine".