19813973 has 4 divisors (see below), whose sum is σ = 19834188. Its totient is φ = 19793760.

The previous prime is 19813967. The next prime is 19813987. The reversal of 19813973 is 37931891.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17497489 + 2316484 = 4183^2 + 1522^2 .

It is a cyclic number.

It is not a de Polignac number, because 19813973 - 2⁴ = 19813957 is a prime.

It is a super-3 number, since 3×19813973³ (a number of 23 digits) contains 333 as substring.

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 19813973.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19813933) 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, 8558 + ... + 10623.

It is an arithmetic number, because the mean of its divisors is an integer number (4958547).

Almost surely, 2^19813973 is an apocalyptic number.

It is an amenable number.

19813973 is a deficient number, since it is larger than the sum of its proper divisors (20215).

19813973 is a wasteful number, since it uses less digits than its factorization.

19813973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20214.

The product of its digits is 40824, while the sum is 41.

The square root of 19813973 is about 4451.2889144606. The cubic root of 19813973 is about 270.5975471693.

The spelling of 19813973 in words is "nineteen million, eight hundred thirteen thousand, nine hundred seventy-three".