19909453 has 4 divisors (see below), whose sum is σ = 19928700. Its totient is φ = 19890208.

The previous prime is 19909451. The next prime is 19909469. The reversal of 19909453 is 35490991.

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 5673924 + 14235529 = 2382^2 + 3773^2 .

It is a cyclic number.

It is not a de Polignac number, because 19909453 - 2¹ = 19909451 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19909451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7978 + ... + 10171.

It is an arithmetic number, because the mean of its divisors is an integer number (4982175).

Almost surely, 2^19909453 is an apocalyptic number.

It is an amenable number.

19909453 is a deficient number, since it is larger than the sum of its proper divisors (19247).

19909453 is a wasteful number, since it uses less digits than its factorization.

19909453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19246.

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 19909453 is about 4462.0010085162. The cubic root of 19909453 is about 271.0315046229.

The spelling of 19909453 in words is "nineteen million, nine hundred nine thousand, four hundred fifty-three".