16556971 has 4 divisors (see below), whose sum is σ = 16565472. Its totient is φ = 16548472.

The previous prime is 16556957. The next prime is 16556977. The reversal of 16556971 is 17965561.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 17965561 = 2417 ⋅7433.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16556971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16556977) 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, 285 + ... + 5761.

It is an arithmetic number, because the mean of its divisors is an integer number (4141368).

Almost surely, 2^16556971 is an apocalyptic number.

16556971 is a deficient number, since it is larger than the sum of its proper divisors (8501).

16556971 is an equidigital number, since it uses as much as digits as its factorization.

16556971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8500.

The product of its digits is 56700, while the sum is 40.

The square root of 16556971 is about 4069.0258047842. The cubic root of 16556971 is about 254.8748379743.

The spelling of 16556971 in words is "sixteen million, five hundred fifty-six thousand, nine hundred seventy-one".