13123991 has 2 divisors, whose sum is σ = 13123992. Its totient is φ = 13123990.

The previous prime is 13123969. The next prime is 13123997. The reversal of 13123991 is 19932131.

It is a strong prime.

It is an emirp because it is prime and its reverse (19932131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13123991 - 2¹⁸ = 12861847 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13123997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6561995 + 6561996.

It is an arithmetic number, because the mean of its divisors is an integer number (6561996).

Almost surely, 2^13123991 is an apocalyptic number.

13123991 is a deficient number, since it is larger than the sum of its proper divisors (1).

13123991 is an equidigital number, since it uses as much as digits as its factorization.

13123991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1458, while the sum is 29.

The square root of 13123991 is about 3622.7049286410. The cubic root of 13123991 is about 235.8786542219.

The spelling of 13123991 in words is "thirteen million, one hundred twenty-three thousand, nine hundred ninety-one".