16566121 has 32 divisors (see below), whose sum is σ = 20837376. Its totient is φ = 12960000.

The previous prime is 16566101. The next prime is 16566131. The reversal of 16566121 is 12166561.

It is a 4-Lehmer number, since φ(16566121) divides (16566121-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 16566121 - 2⁷ = 16565993 is a prime.

It is a deceptive number, since it divides R_16566120.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16566121.

It is not an unprimeable number, because it can be changed into a prime (16566101) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 163971 + ... + 164071.

It is an arithmetic number, because the mean of its divisors is an integer number (651168).

Almost surely, 2^16566121 is an apocalyptic number.

16566121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16566121 is a deficient number, since it is larger than the sum of its proper divisors (4271255).

16566121 is a wasteful number, since it uses less digits than its factorization.

16566121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193.

The product of its digits is 2160, while the sum is 28.

The square root of 16566121 is about 4070.1499972360. The cubic root of 16566121 is about 254.9217804433.

It can be divided in two parts, 1656 and 6121, that added together give a palindrome (7777).

The spelling of 16566121 in words is "sixteen million, five hundred sixty-six thousand, one hundred twenty-one".