19899091 has 2 divisors, whose sum is σ = 19899092. Its totient is φ = 19899090.

The previous prime is 19899083. The next prime is 19899109. The reversal of 19899091 is 19099891.

Together with next prime (19899109) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19899091 - 2³ = 19899083 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19899791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9949545 + 9949546.

It is an arithmetic number, because the mean of its divisors is an integer number (9949546).

Almost surely, 2^19899091 is an apocalyptic number.

19899091 is a deficient number, since it is larger than the sum of its proper divisors (1).

19899091 is an equidigital number, since it uses as much as digits as its factorization.

19899091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 19899091 is about 4460.8397191560. The cubic root of 19899091 is about 270.9844764463.

The spelling of 19899091 in words is "nineteen million, eight hundred ninety-nine thousand, ninety-one".