1943981 has 8 divisors (see below), whose sum is σ = 2105880. Its totient is φ = 1783872.

The previous prime is 1943959. The next prime is 1943993. The reversal of 1943981 is 1893491.

It can be written as a sum of positive squares in 4 ways, for example, as 188356 + 1755625 = 434^2 + 1325^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1943981 - 2¹⁸ = 1681837 is a prime.

It is a super-2 number, since 2×1943981² = 7558124256722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1943911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2651 + ... + 3303.

It is an arithmetic number, because the mean of its divisors is an integer number (263235).

2^1943981 is an apocalyptic number.

It is an amenable number.

1943981 is a deficient number, since it is larger than the sum of its proper divisors (161899).

1943981 is a wasteful number, since it uses less digits than its factorization.

1943981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 895.

The product of its digits is 7776, while the sum is 35.

The square root of 1943981 is about 1394.2671910362. The cubic root of 1943981 is about 124.8046227810.

The spelling of 1943981 in words is "one million, nine hundred forty-three thousand, nine hundred eighty-one".