12154991 has 2 divisors, whose sum is σ = 12154992. Its totient is φ = 12154990.

The previous prime is 12154979. The next prime is 12154993. The reversal of 12154991 is 19945121.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12154991 is a prime.

Together with 12154993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12154993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6077495 + 6077496.

It is an arithmetic number, because the mean of its divisors is an integer number (6077496).

Almost surely, 2^12154991 is an apocalyptic number.

12154991 is a deficient number, since it is larger than the sum of its proper divisors (1).

12154991 is an equidigital number, since it uses as much as digits as its factorization.

12154991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 32.

The square root of 12154991 is about 3486.4008662229. The cubic root of 12154991 is about 229.9243040127.

The spelling of 12154991 in words is "twelve million, one hundred fifty-four thousand, nine hundred ninety-one".