18869509 has 4 divisors (see below), whose sum is σ = 18996300. Its totient is φ = 18742720.

The previous prime is 18869503. The next prime is 18869549. The reversal of 18869509 is 90596881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90596881 = 359 ⋅252359.

It can be written as a sum of positive squares in 2 ways, for example, as 3045025 + 15824484 = 1745^2 + 3978^2 .

It is a cyclic number.

It is not a de Polignac number, because 18869509 - 2⁷ = 18869381 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 (18869503) 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, 63172 + ... + 63469.

It is an arithmetic number, because the mean of its divisors is an integer number (4749075).

Almost surely, 2^18869509 is an apocalyptic number.

It is an amenable number.

18869509 is a deficient number, since it is larger than the sum of its proper divisors (126791).

18869509 is a wasteful number, since it uses less digits than its factorization.

18869509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126790.

The product of its (nonzero) digits is 155520, while the sum is 46.

The square root of 18869509 is about 4343.9048101909. The cubic root of 18869509 is about 266.2278796085.

The spelling of 18869509 in words is "eighteen million, eight hundred sixty-nine thousand, five hundred nine".