19986091 has 2 divisors, whose sum is σ = 19986092. Its totient is φ = 19986090.

The previous prime is 19986079. The next prime is 19986121. The reversal of 19986091 is 19068991.

It is a weak prime.

It is an emirp because it is prime and its reverse (19068991) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 16098661 and 16689061.

It is a cyclic number.

It is not a de Polignac number, because 19986091 - 2⁷ = 19985963 is a prime.

It is not a weakly prime, because it can be changed into another prime (19986061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9993045 + 9993046.

It is an arithmetic number, because the mean of its divisors is an integer number (9993046).

Almost surely, 2^19986091 is an apocalyptic number.

19986091 is a deficient number, since it is larger than the sum of its proper divisors (1).

19986091 is an equidigital number, since it uses as much as digits as its factorization.

19986091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 19986091 is about 4470.5806110616. The cubic root of 19986091 is about 271.3788223425.

The spelling of 19986091 in words is "nineteen million, nine hundred eighty-six thousand, ninety-one".