1389781 has 4 divisors (see below), whose sum is σ = 1410592. Its totient is φ = 1368972.

The previous prime is 1389769. The next prime is 1389797. The reversal of 1389781 is 1879831.

1389781 is nontrivially palindromic in base 8.

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: 1879831 = 43 ⋅43717.

It is a cyclic number.

It is not a de Polignac number, because 1389781 - 2⁵ = 1389749 is a prime.

It is a super-2 number, since 2×1389781² = 3862982455922, which contains 22 as substring.

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 1389781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1389281) 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, 10305 + ... + 10438.

It is an arithmetic number, because the mean of its divisors is an integer number (352648).

2^1389781 is an apocalyptic number.

It is an amenable number.

1389781 is a deficient number, since it is larger than the sum of its proper divisors (20811).

1389781 is an equidigital number, since it uses as much as digits as its factorization.

1389781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20810.

The product of its digits is 12096, while the sum is 37.

The square root of 1389781 is about 1178.8897319088. The cubic root of 1389781 is about 111.5960415771.

The spelling of 1389781 in words is "one million, three hundred eighty-nine thousand, seven hundred eighty-one".