2181381 has 8 divisors (see below), whose sum is σ = 2924064. Its totient is φ = 1446480.

The previous prime is 2181379. The next prime is 2181419. The reversal of 2181381 is 1831812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2181381 - 2¹ = 2181379 is a prime.

It is a super-2 number, since 2×2181381² = 9516846134322, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1255 + ... + 2436.

It is an arithmetic number, because the mean of its divisors is an integer number (365508).

2^2181381 is an apocalyptic number.

It is an amenable number.

2181381 is a deficient number, since it is larger than the sum of its proper divisors (742683).

2181381 is a wasteful number, since it uses less digits than its factorization.

2181381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3891.

The product of its digits is 384, while the sum is 24.

The square root of 2181381 is about 1476.9498975930. The cubic root of 2181381 is about 129.6912000009.

The spelling of 2181381 in words is "two million, one hundred eighty-one thousand, three hundred eighty-one".