19996491 has 4 divisors (see below), whose sum is σ = 26661992. Its totient is φ = 13330992.

The previous prime is 19996489. The next prime is 19996513. The reversal of 19996491 is 19469991.

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

It is not a de Polignac number, because 19996491 - 2¹ = 19996489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19996491.

It is not an unprimeable number, because it can be changed into a prime (19996411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3332746 + ... + 3332751.

It is an arithmetic number, because the mean of its divisors is an integer number (6665498).

Almost surely, 2^19996491 is an apocalyptic number.

19996491 is a deficient number, since it is larger than the sum of its proper divisors (6665501).

19996491 is an equidigital number, since it uses as much as digits as its factorization.

19996491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6665500.

The product of its digits is 157464, while the sum is 48.

The square root of 19996491 is about 4471.7436196634. The cubic root of 19996491 is about 271.4258859120.

The spelling of 19996491 in words is "nineteen million, nine hundred ninety-six thousand, four hundred ninety-one".