18406368509 has 4 divisors (see below), whose sum is σ = 18474288960. Its totient is φ = 18338448060.

The previous prime is 18406368419. The next prime is 18406368529. The reversal of 18406368509 is 90586360481.

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.

It is a cyclic number.

It is not a de Polignac number, because 18406368509 - 2¹⁶ = 18406302973 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 (18406368529) 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, 33959819 + ... + 33960360.

It is an arithmetic number, because the mean of its divisors is an integer number (4618572240).

Almost surely, 2^18406368509 is an apocalyptic number.

It is an amenable number.

18406368509 is a deficient number, since it is larger than the sum of its proper divisors (67920451).

18406368509 is an equidigital number, since it uses as much as digits as its factorization.

18406368509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67920450.

The product of its (nonzero) digits is 1244160, while the sum is 50.

The spelling of 18406368509 in words is "eighteen billion, four hundred six million, three hundred sixty-eight thousand, five hundred nine".