1981121 has 4 divisors (see below), whose sum is σ = 1993152. Its totient is φ = 1969092.

The previous prime is 1981099. The next prime is 1981141. The reversal of 1981121 is 1211891.

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: 1211891 = 317 ⋅3823.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (1981141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5765 + ... + 6098.

It is an arithmetic number, because the mean of its divisors is an integer number (498288).

2^1981121 is an apocalyptic number.

It is an amenable number.

1981121 is a deficient number, since it is larger than the sum of its proper divisors (12031).

1981121 is a wasteful number, since it uses less digits than its factorization.

1981121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12030.

The product of its digits is 144, while the sum is 23.

The square root of 1981121 is about 1407.5230015883. The cubic root of 1981121 is about 125.5944168681.

The spelling of 1981121 in words is "one million, nine hundred eighty-one thousand, one hundred twenty-one".