19891225 has 6 divisors (see below), whose sum is σ = 24665150. Its totient is φ = 15912960.

The previous prime is 19891213. The next prime is 19891229. The reversal of 19891225 is 52219891.

It can be written as a sum of positive squares in 3 ways, for example, as 811801 + 19079424 = 901^2 + 4368^2 .

It is not a de Polignac number, because 19891225 - 2⁹ = 19890713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19891229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 397800 + ... + 397849.

Almost surely, 2^19891225 is an apocalyptic number.

It is an amenable number.

19891225 is a deficient number, since it is larger than the sum of its proper divisors (4773925).

19891225 is an equidigital number, since it uses as much as digits as its factorization.

19891225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795659 (or 795654 counting only the distinct ones).

The product of its digits is 12960, while the sum is 37.

The square root of 19891225 is about 4459.9579594431. The cubic root of 19891225 is about 270.9487655217.

The spelling of 19891225 in words is "nineteen million, eight hundred ninety-one thousand, two hundred twenty-five".