19724849 has 4 divisors (see below), whose sum is σ = 19868964. Its totient is φ = 19580736.

The previous prime is 19724839. The next prime is 19724857. The reversal of 19724849 is 94842791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94842791 = 1901 ⋅49891.

It can be written as a sum of positive squares in 2 ways, for example, as 15460624 + 4264225 = 3932^2 + 2065^2 .

It is a cyclic number.

It is not a de Polignac number, because 19724849 - 2⁴ = 19724833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19724839) 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, 71852 + ... + 72125.

It is an arithmetic number, because the mean of its divisors is an integer number (4967241).

Almost surely, 2^19724849 is an apocalyptic number.

It is an amenable number.

19724849 is a deficient number, since it is larger than the sum of its proper divisors (144115).

19724849 is a wasteful number, since it uses less digits than its factorization.

19724849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144114.

The product of its digits is 145152, while the sum is 44.

The square root of 19724849 is about 4441.2665986180. The cubic root of 19724849 is about 270.1912179968.

The spelling of 19724849 in words is "nineteen million, seven hundred twenty-four thousand, eight hundred forty-nine".