19949509 has 4 divisors (see below), whose sum is σ = 20230560. Its totient is φ = 19668460.

The previous prime is 19949497. The next prime is 19949537. The reversal of 19949509 is 90594991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90594991 = 47 ⋅1927553.

It is a cyclic number.

It is not a de Polignac number, because 19949509 - 2⁹ = 19948997 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 (19949539) 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, 140419 + ... + 140560.

It is an arithmetic number, because the mean of its divisors is an integer number (5057640).

Almost surely, 2^19949509 is an apocalyptic number.

It is an amenable number.

19949509 is a deficient number, since it is larger than the sum of its proper divisors (281051).

19949509 is an equidigital number, since it uses as much as digits as its factorization.

19949509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281050.

The product of its (nonzero) digits is 131220, while the sum is 46.

The square root of 19949509 is about 4466.4873222702. The cubic root of 19949509 is about 271.2131464014.

The spelling of 19949509 in words is "nineteen million, nine hundred forty-nine thousand, five hundred nine".