18929342809 has 4 divisors (see below), whose sum is σ = 20385446116. Its totient is φ = 17473239504.

The previous prime is 18929342777. The next prime is 18929342813. The reversal of 18929342809 is 90824392981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90824392981 = 7 ⋅12974913283.

It can be written as a sum of positive squares in 2 ways, for example, as 1365672025 + 17563670784 = 36955^2 + 132528^2 .

It is a cyclic number.

It is not a de Polignac number, because 18929342809 - 2⁵ = 18929342777 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18929342809.

It is not an unprimeable number, because it can be changed into a prime (18929342899) 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, 728051634 + ... + 728051659.

It is an arithmetic number, because the mean of its divisors is an integer number (5096361529).

Almost surely, 2^18929342809 is an apocalyptic number.

It is an amenable number.

18929342809 is a deficient number, since it is larger than the sum of its proper divisors (1456103307).

18929342809 is a wasteful number, since it uses less digits than its factorization.

18929342809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1456103306.

The product of its (nonzero) digits is 2239488, while the sum is 55.

The spelling of 18929342809 in words is "eighteen billion, nine hundred twenty-nine million, three hundred forty-two thousand, eight hundred nine".