19491139 has 4 divisors (see below), whose sum is σ = 19726056. Its totient is φ = 19256224.

The previous prime is 19491107. The next prime is 19491151. The reversal of 19491139 is 93119491.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19491139 - 2⁵ = 19491107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19491098 and 19491107.

It is not an unprimeable number, because it can be changed into a prime (19492139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 117334 + ... + 117499.

It is an arithmetic number, because the mean of its divisors is an integer number (4931514).

Almost surely, 2^19491139 is an apocalyptic number.

19491139 is a deficient number, since it is larger than the sum of its proper divisors (234917).

19491139 is an equidigital number, since it uses as much as digits as its factorization.

19491139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234916.

The product of its digits is 8748, while the sum is 37.

The square root of 19491139 is about 4414.8770084794. The cubic root of 19491139 is about 269.1198546437.

The spelling of 19491139 in words is "nineteen million, four hundred ninety-one thousand, one hundred thirty-nine".