16166981 has 4 divisors (see below), whose sum is σ = 16175052. Its totient is φ = 16158912.

The previous prime is 16166977. The next prime is 16166987. The reversal of 16166981 is 18966161.

16166981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 18966161 = 19 ⋅998219.

It can be written as a sum of positive squares in 2 ways, for example, as 4884100 + 11282881 = 2210^2 + 3359^2 .

It is a cyclic number.

It is not a de Polignac number, because 16166981 - 2² = 16166977 is a prime.

It is a super-2 number, since 2×16166981² = 522742549308722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16166987) 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, 1511 + ... + 5883.

It is an arithmetic number, because the mean of its divisors is an integer number (4043763).

Almost surely, 2^16166981 is an apocalyptic number.

It is an amenable number.

16166981 is a deficient number, since it is larger than the sum of its proper divisors (8071).

16166981 is an equidigital number, since it uses as much as digits as its factorization.

16166981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8070.

The product of its digits is 15552, while the sum is 38.

The square root of 16166981 is about 4020.8184490225. The cubic root of 16166981 is about 252.8577733835.

The spelling of 16166981 in words is "sixteen million, one hundred sixty-six thousand, nine hundred eighty-one".