19428509 has 2 divisors, whose sum is σ = 19428510. Its totient is φ = 19428508.

The previous prime is 19428473. The next prime is 19428517. The reversal of 19428509 is 90582491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17935225 + 1493284 = 4235^2 + 1222^2 .

It is a cyclic number.

It is not a de Polignac number, because 19428509 - 2²⁴ = 2651293 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19428109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9714254 + 9714255.

It is an arithmetic number, because the mean of its divisors is an integer number (9714255).

Almost surely, 2^19428509 is an apocalyptic number.

It is an amenable number.

19428509 is a deficient number, since it is larger than the sum of its proper divisors (1).

19428509 is an equidigital number, since it uses as much as digits as its factorization.

19428509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 19428509 is about 4407.7782385233. The cubic root of 19428509 is about 268.8312951106.

The spelling of 19428509 in words is "nineteen million, four hundred twenty-eight thousand, five hundred nine".