19721874 has 16 divisors (see below), whose sum is σ = 39489408. Its totient is φ = 6566352.

The previous prime is 19721873. The next prime is 19721881. The reversal of 19721874 is 47812791.

It is not an unprimeable number, because it can be changed into a prime (19721873) 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 7 ways as a sum of consecutive naturals, for example, 6724 + ... + 9200.

It is an arithmetic number, because the mean of its divisors is an integer number (2468088).

Almost surely, 2^19721874 is an apocalyptic number.

19721874 is an abundant number, since it is smaller than the sum of its proper divisors (19767534).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19721874 is a wasteful number, since it uses less digits than its factorization.

19721874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3809.

The product of its digits is 28224, while the sum is 39.

The square root of 19721874 is about 4440.9316590103. The cubic root of 19721874 is about 270.1776334520.

The spelling of 19721874 in words is "nineteen million, seven hundred twenty-one thousand, eight hundred seventy-four".