12172991 has 2 divisors, whose sum is σ = 12172992. Its totient is φ = 12172990.

The previous prime is 12172973. The next prime is 12172997. The reversal of 12172991 is 19927121.

It is a strong prime.

It is an emirp because it is prime and its reverse (19927121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12172991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12172997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6086495 + 6086496.

It is an arithmetic number, because the mean of its divisors is an integer number (6086496).

Almost surely, 2^12172991 is an apocalyptic number.

12172991 is a deficient number, since it is larger than the sum of its proper divisors (1).

12172991 is an equidigital number, since it uses as much as digits as its factorization.

12172991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 32.

The square root of 12172991 is about 3488.9813699703. The cubic root of 12172991 is about 230.0377442782.

The spelling of 12172991 in words is "twelve million, one hundred seventy-two thousand, nine hundred ninety-one".