1381391 has 8 divisors (see below), whose sum is σ = 1555968. Its totient is φ = 1215000.

The previous prime is 1381381. The next prime is 1381397. The reversal of 1381391 is 1931831.

1381391 = 240² + 241² + ... + 261².

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 1381391 - 2⁶ = 1381327 is a prime.

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 1381391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1381397) 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, 1685 + ... + 2366.

It is an arithmetic number, because the mean of its divisors is an integer number (194496).

2^1381391 is an apocalyptic number.

1381391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1381391 is a deficient number, since it is larger than the sum of its proper divisors (174577).

1381391 is a wasteful number, since it uses less digits than its factorization.

1381391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4093.

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

The square root of 1381391 is about 1175.3259122473. The cubic root of 1381391 is about 111.3710226141.

The spelling of 1381391 in words is "one million, three hundred eighty-one thousand, three hundred ninety-one".