1981389 has 8 divisors (see below), whose sum is σ = 2650752. Its totient is φ = 1316480.

The previous prime is 1981361. The next prime is 1981393. The reversal of 1981389 is 9831891.

It is a happy number.

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 1981389 - 2⁹ = 1980877 is a prime.

It is a super-3 number, since 3×1981389³ = 23336219308939700607, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981349) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124 + ... + 1994.

It is an arithmetic number, because the mean of its divisors is an integer number (331344).

2^1981389 is an apocalyptic number.

It is an amenable number.

1981389 is a deficient number, since it is larger than the sum of its proper divisors (669363).

1981389 is a wasteful number, since it uses less digits than its factorization.

1981389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2227.

The product of its digits is 15552, while the sum is 39.

The square root of 1981389 is about 1407.6182010758. The cubic root of 1981389 is about 125.6000799559.

The spelling of 1981389 in words is "one million, nine hundred eighty-one thousand, three hundred eighty-nine".