1881389 has 2 divisors, whose sum is σ = 1881390. Its totient is φ = 1881388.

The previous prime is 1881349. The next prime is 1881391. The reversal of 1881389 is 9831881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1876900 + 4489 = 1370^2 + 67^2 .

It is an emirp because it is prime and its reverse (9831881) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1881389 is a prime.

Together with 1881391, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1881329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 940694 + 940695.

It is an arithmetic number, because the mean of its divisors is an integer number (940695).

2^1881389 is an apocalyptic number.

It is an amenable number.

1881389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1881389 is an equidigital number, since it uses as much as digits as its factorization.

1881389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 38.

The square root of 1881389 is about 1371.6373427404. The cubic root of 1881389 is about 123.4505038589.

The spelling of 1881389 in words is "one million, eight hundred eighty-one thousand, three hundred eighty-nine".