19491138 has 16 divisors (see below), whose sum is σ = 43313760. Its totient is φ = 6497028.

The previous prime is 19491107. The next prime is 19491151. The reversal of 19491138 is 83119491.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180420 + ... + 180527.

It is an arithmetic number, because the mean of its divisors is an integer number (2707110).

Almost surely, 2^19491138 is an apocalyptic number.

19491138 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19491138 is an abundant number, since it is smaller than the sum of its proper divisors (23822622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19491138 is a wasteful number, since it uses less digits than its factorization.

19491138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360958 (or 360952 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 19491138 is about 4414.8768952260. The cubic root of 19491138 is about 269.1198500412.

The spelling of 19491138 in words is "nineteen million, four hundred ninety-one thousand, one hundred thirty-eight".