16561199 has 4 divisors (see below), whose sum is σ = 16645464. Its totient is φ = 16476936.

The previous prime is 16561189. The next prime is 16561211. The reversal of 16561199 is 99116561.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16561199 - 2¹² = 16557103 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 (16561169) 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, 41837 + ... + 42230.

It is an arithmetic number, because the mean of its divisors is an integer number (4161366).

Almost surely, 2^16561199 is an apocalyptic number.

16561199 is a deficient number, since it is larger than the sum of its proper divisors (84265).

16561199 is an equidigital number, since it uses as much as digits as its factorization.

16561199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84264.

The product of its digits is 14580, while the sum is 38.

The square root of 16561199 is about 4069.5453062965. The cubic root of 16561199 is about 254.8965311350.

The spelling of 16561199 in words is "sixteen million, five hundred sixty-one thousand, one hundred ninety-nine".