18129491 has 2 divisors, whose sum is σ = 18129492. Its totient is φ = 18129490.

The previous prime is 18129487. The next prime is 18129493. The reversal of 18129491 is 19492181.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18129491 - 2² = 18129487 is a prime.

Together with 18129493, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18129493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9064745 + 9064746.

It is an arithmetic number, because the mean of its divisors is an integer number (9064746).

Almost surely, 2^18129491 is an apocalyptic number.

18129491 is a deficient number, since it is larger than the sum of its proper divisors (1).

18129491 is an equidigital number, since it uses as much as digits as its factorization.

18129491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 35.

The square root of 18129491 is about 4257.8740000146. The cubic root of 18129491 is about 262.7010873393.

The spelling of 18129491 in words is "eighteen million, one hundred twenty-nine thousand, four hundred ninety-one".