18846991 has 2 divisors, whose sum is σ = 18846992. Its totient is φ = 18846990.

The previous prime is 18846983. The next prime is 18847001. The reversal of 18846991 is 19964881.

It is a weak prime.

It is an emirp because it is prime and its reverse (19964881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18846991 - 2³ = 18846983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18846941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9423495 + 9423496.

It is an arithmetic number, because the mean of its divisors is an integer number (9423496).

Almost surely, 2^18846991 is an apocalyptic number.

18846991 is a deficient number, since it is larger than the sum of its proper divisors (1).

18846991 is an equidigital number, since it uses as much as digits as its factorization.

18846991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 46.

The square root of 18846991 is about 4341.3121288385. The cubic root of 18846991 is about 266.1219361053.

The spelling of 18846991 in words is "eighteen million, eight hundred forty-six thousand, nine hundred ninety-one".