12691993 has 4 divisors (see below), whose sum is σ = 12701988. Its totient is φ = 12682000.

The previous prime is 12691957. The next prime is 12691997. The reversal of 12691993 is 39919621.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 5890329 + 6801664 = 2427^2 + 2608^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12691993 is a prime.

It is a super-2 number, since 2×12691993² = 322173372624098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12691997) 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, 2758 + ... + 5743.

It is an arithmetic number, because the mean of its divisors is an integer number (3175497).

Almost surely, 2^12691993 is an apocalyptic number.

It is an amenable number.

12691993 is a deficient number, since it is larger than the sum of its proper divisors (9995).

12691993 is an equidigital number, since it uses as much as digits as its factorization.

12691993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9994.

The product of its digits is 26244, while the sum is 40.

The square root of 12691993 is about 3562.5823499254. The cubic root of 12691993 is about 233.2616131048.

The spelling of 12691993 in words is "twelve million, six hundred ninety-one thousand, nine hundred ninety-three".