16169981 has 4 divisors (see below), whose sum is σ = 16411392. Its totient is φ = 15928572.

The previous prime is 16169971. The next prime is 16169983. The reversal of 16169981 is 18996161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18996161 = 41 ⋅463321.

It is a cyclic number.

It is not a de Polignac number, because 16169981 - 2⁶ = 16169917 is a prime.

It is a super-2 number, since 2×16169981² = 522936571080722, 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 (16169983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120605 + ... + 120738.

It is an arithmetic number, because the mean of its divisors is an integer number (4102848).

Almost surely, 2^16169981 is an apocalyptic number.

It is an amenable number.

16169981 is a deficient number, since it is larger than the sum of its proper divisors (241411).

16169981 is an equidigital number, since it uses as much as digits as its factorization.

16169981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241410.

The product of its digits is 23328, while the sum is 41.

The square root of 16169981 is about 4021.1914900935. The cubic root of 16169981 is about 252.8734127991.

The spelling of 16169981 in words is "sixteen million, one hundred sixty-nine thousand, nine hundred eighty-one".