19198991 has 8 divisors (see below), whose sum is σ = 22188960. Its totient is φ = 16270848.

The previous prime is 19198969. The next prime is 19199023. The reversal of 19198991 is 19989191.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19198991 - 2¹⁰ = 19197967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19198901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14786 + ... + 16031.

It is an arithmetic number, because the mean of its divisors is an integer number (2773620).

Almost surely, 2^19198991 is an apocalyptic number.

19198991 is a deficient number, since it is larger than the sum of its proper divisors (2989969).

19198991 is an equidigital number, since it uses as much as digits as its factorization.

19198991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30913.

The product of its digits is 52488, while the sum is 47.

The square root of 19198991 is about 4381.6653226827. The cubic root of 19198991 is about 267.7684892712.

The spelling of 19198991 in words is "nineteen million, one hundred ninety-eight thousand, nine hundred ninety-one".