1243981 has 4 divisors (see below), whose sum is σ = 1274364. Its totient is φ = 1213600.

The previous prime is 1243969. The next prime is 1243997. The reversal of 1243981 is 1893421.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1893421 = 41 ⋅46181.

It can be written as a sum of positive squares in 2 ways, for example, as 122500 + 1121481 = 350^2 + 1059^2 .

It is not a de Polignac number, because 1243981 - 2¹³ = 1235789 is a prime.

It is a super-2 number, since 2×1243981² = 3094977456722, 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 (1243951) 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 3 ways as a sum of consecutive naturals, for example, 15130 + ... + 15211.

It is an arithmetic number, because the mean of its divisors is an integer number (318591).

2^1243981 is an apocalyptic number.

It is an amenable number.

1243981 is a deficient number, since it is larger than the sum of its proper divisors (30383).

1243981 is an equidigital number, since it uses as much as digits as its factorization.

1243981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30382.

The product of its digits is 1728, while the sum is 28.

The square root of 1243981 is about 1115.3389619304. The cubic root of 1243981 is about 107.5485556746.

The spelling of 1243981 in words is "one million, two hundred forty-three thousand, nine hundred eighty-one".