2168981 has 4 divisors (see below), whose sum is σ = 2172192. Its totient is φ = 2165772.

The previous prime is 2168953. The next prime is 2168987. The reversal of 2168981 is 1898612.

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.

It is a cyclic number.

It is not a de Polignac number, because 2168981 - 2⁶ = 2168917 is a prime.

It is a super-2 number, since 2×2168981² = 9408957156722, 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 (2168987) 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, 155 + ... + 2088.

It is an arithmetic number, because the mean of its divisors is an integer number (543048).

2^2168981 is an apocalyptic number.

It is an amenable number.

2168981 is a deficient number, since it is larger than the sum of its proper divisors (3211).

2168981 is an equidigital number, since it uses as much as digits as its factorization.

2168981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3210.

The product of its digits is 6912, while the sum is 35.

The square root of 2168981 is about 1472.7460745152. The cubic root of 2168981 is about 129.4449908730. Note that the first 3 decimals are identical.

The spelling of 2168981 in words is "two million, one hundred sixty-eight thousand, nine hundred eighty-one".