16555891 has 16 divisors (see below), whose sum is σ = 19058688. Its totient is φ = 14241600.

The previous prime is 16555867. The next prime is 16555907. The reversal of 16555891 is 19855561.

It is a cyclic number.

It is not a de Polignac number, because 16555891 - 2¹⁷ = 16424819 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16555811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15511 + ... + 16543.

It is an arithmetic number, because the mean of its divisors is an integer number (1191168).

Almost surely, 2^16555891 is an apocalyptic number.

16555891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16555891 is a deficient number, since it is larger than the sum of its proper divisors (2502797).

16555891 is a wasteful number, since it uses less digits than its factorization.

16555891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122.

The product of its digits is 54000, while the sum is 40.

The square root of 16555891 is about 4068.8930927219. The cubic root of 16555891 is about 254.8692960828.

It can be divided in two parts, 165558 and 91, that added together give a square (165649 = 407²).

The spelling of 16555891 in words is "sixteen million, five hundred fifty-five thousand, eight hundred ninety-one".