19712813 has 4 divisors (see below), whose sum is σ = 19868160. Its totient is φ = 19557468.

The previous prime is 19712801. The next prime is 19712857. The reversal of 19712813 is 31821791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31821791 = 181 ⋅175811.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19712813 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 19712813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19712213) 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, 77483 + ... + 77736.

It is an arithmetic number, because the mean of its divisors is an integer number (4967040).

Almost surely, 2^19712813 is an apocalyptic number.

It is an amenable number.

19712813 is a deficient number, since it is larger than the sum of its proper divisors (155347).

19712813 is a wasteful number, since it uses less digits than its factorization.

19712813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155346.

The product of its digits is 3024, while the sum is 32.

The square root of 19712813 is about 4439.9113729893. The cubic root of 19712813 is about 270.1362503909.

The spelling of 19712813 in words is "nineteen million, seven hundred twelve thousand, eight hundred thirteen".