19730509 has 4 divisors (see below), whose sum is σ = 20263804. Its totient is φ = 19197216.

The previous prime is 19730497. The next prime is 19730519. The reversal of 19730509 is 90503791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90503791 = 7 ⋅12929113.

It can be written as a sum of positive squares in 2 ways, for example, as 15642025 + 4088484 = 3955^2 + 2022^2 .

It is a cyclic number.

It is not a de Polignac number, because 19730509 - 2¹³ = 19722317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19730519) 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, 266592 + ... + 266665.

It is an arithmetic number, because the mean of its divisors is an integer number (5065951).

Almost surely, 2^19730509 is an apocalyptic number.

It is an amenable number.

19730509 is a deficient number, since it is larger than the sum of its proper divisors (533295).

19730509 is an equidigital number, since it uses as much as digits as its factorization.

19730509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533294.

The product of its (nonzero) digits is 8505, while the sum is 34.

The square root of 19730509 is about 4441.9037585252. The cubic root of 19730509 is about 270.2170591079.

The spelling of 19730509 in words is "nineteen million, seven hundred thirty thousand, five hundred nine".