12381391 has 4 divisors (see below), whose sum is σ = 13506984. Its totient is φ = 11255800.

The previous prime is 12381379. The next prime is 12381409. The reversal of 12381391 is 19318321.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 12381391 - 2¹¹ = 12379343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12381361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 562780 + ... + 562801.

It is an arithmetic number, because the mean of its divisors is an integer number (3376746).

Almost surely, 2^12381391 is an apocalyptic number.

12381391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

12381391 is a deficient number, since it is larger than the sum of its proper divisors (1125593).

12381391 is a wasteful number, since it uses less digits than its factorization.

12381391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1125592.

The product of its digits is 1296, while the sum is 28.

The square root of 12381391 is about 3518.7200798017. The cubic root of 12381391 is about 231.3430620327.

It can be divided in two parts, 123813 and 91, that added together give a square (123904 = 352²).

The spelling of 12381391 in words is "twelve million, three hundred eighty-one thousand, three hundred ninety-one".