19930813 has 4 divisors (see below), whose sum is σ = 22778080. Its totient is φ = 17083548.

The previous prime is 19930787. The next prime is 19930843. The reversal of 19930813 is 31803991.

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.

It is a cyclic number.

It is not a de Polignac number, because 19930813 - 2⁹ = 19930301 is a prime.

It is a super-3 number, since 3×19930813³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19930843) 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, 1423623 + ... + 1423636.

It is an arithmetic number, because the mean of its divisors is an integer number (5694520).

Almost surely, 2^19930813 is an apocalyptic number.

It is an amenable number.

19930813 is a deficient number, since it is larger than the sum of its proper divisors (2847267).

19930813 is an equidigital number, since it uses as much as digits as its factorization.

19930813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2847266.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 19930813 is about 4464.3939118317. The cubic root of 19930813 is about 271.1283960147.

The spelling of 19930813 in words is "nineteen million, nine hundred thirty thousand, eight hundred thirteen".