1981331 has 8 divisors (see below), whose sum is σ = 2172528. Its totient is φ = 1792000.

The previous prime is 1981297. The next prime is 1981337. The reversal of 1981331 is 1331891.

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 1981331 - 2⁶ = 1981267 is a prime.

It is a super-3 number, since 3×1981331³ = 23334170047890863073, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1981331.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981337) 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, 2771 + ... + 3411.

It is an arithmetic number, because the mean of its divisors is an integer number (271566).

2^1981331 is an apocalyptic number.

1981331 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1981331 is a deficient number, since it is larger than the sum of its proper divisors (191197).

1981331 is a wasteful number, since it uses less digits than its factorization.

1981331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 933.

The product of its digits is 648, while the sum is 26.

The square root of 1981331 is about 1407.5975987476. The cubic root of 1981331 is about 125.5988544056.

The spelling of 1981331 in words is "one million, nine hundred eighty-one thousand, three hundred thirty-one".