19498991 has 4 divisors (see below), whose sum is σ = 20171400. Its totient is φ = 18826584.

The previous prime is 19498981. The next prime is 19499041. The reversal of 19498991 is 19989491.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19989491 = 1279 ⋅15629.

It is a cyclic number.

It is not a de Polignac number, because 19498991 - 2¹⁰ = 19497967 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 (19498951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 336161 + ... + 336218.

It is an arithmetic number, because the mean of its divisors is an integer number (5042850).

Almost surely, 2^19498991 is an apocalyptic number.

19498991 is a deficient number, since it is larger than the sum of its proper divisors (672409).

19498991 is an equidigital number, since it uses as much as digits as its factorization.

19498991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672408.

The product of its digits is 209952, while the sum is 50.

The square root of 19498991 is about 4415.7661849333. The cubic root of 19498991 is about 269.1559880785.

The spelling of 19498991 in words is "nineteen million, four hundred ninety-eight thousand, nine hundred ninety-one".