18676991 has 2 divisors, whose sum is σ = 18676992. Its totient is φ = 18676990.

The previous prime is 18676967. The next prime is 18676993. The reversal of 18676991 is 19967681.

It is a strong prime.

It is an emirp because it is prime and its reverse (19967681) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18676991 is a prime.

Together with 18676993, 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 (18676993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9338495 + 9338496.

It is an arithmetic number, because the mean of its divisors is an integer number (9338496).

Almost surely, 2^18676991 is an apocalyptic number.

18676991 is a deficient number, since it is larger than the sum of its proper divisors (1).

18676991 is an equidigital number, since it uses as much as digits as its factorization.

18676991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 47.

The square root of 18676991 is about 4321.6884431898. The cubic root of 18676991 is about 265.3193775996.

It can be divided in two parts, 186 and 76991, that added together give a palindrome (77177).

The spelling of 18676991 in words is "eighteen million, six hundred seventy-six thousand, nine hundred ninety-one".