12691387 has 2 divisors, whose sum is σ = 12691388. Its totient is φ = 12691386.

The previous prime is 12691381. The next prime is 12691391. The reversal of 12691387 is 78319621.

It is a strong prime.

It is an emirp because it is prime and its reverse (78319621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12691387 - 2³ = 12691379 is a prime.

It is a super-2 number, since 2×12691387² = 322142607967538, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (12691381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6345693 + 6345694.

It is an arithmetic number, because the mean of its divisors is an integer number (6345694).

Almost surely, 2^12691387 is an apocalyptic number.

12691387 is a deficient number, since it is larger than the sum of its proper divisors (1).

12691387 is an equidigital number, since it uses as much as digits as its factorization.

12691387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 37.

The square root of 12691387 is about 3562.4972982446. The cubic root of 12691387 is about 233.2579005598.

The spelling of 12691387 in words is "twelve million, six hundred ninety-one thousand, three hundred eighty-seven".