18698891 has 2 divisors, whose sum is σ = 18698892. Its totient is φ = 18698890.

The previous prime is 18698807. The next prime is 18698899. The reversal of 18698891 is 19889681.

It is a happy number.

It is a strong prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 16886981 and 18968861.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18698891 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18698899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9349445 + 9349446.

It is an arithmetic number, because the mean of its divisors is an integer number (9349446).

Almost surely, 2^18698891 is an apocalyptic number.

18698891 is a deficient number, since it is larger than the sum of its proper divisors (1).

18698891 is an equidigital number, since it uses as much as digits as its factorization.

18698891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 50.

The square root of 18698891 is about 4324.2214328131. The cubic root of 18698891 is about 265.4230385656.

The spelling of 18698891 in words is "eighteen million, six hundred ninety-eight thousand, eight hundred ninety-one".