18913808405 has 16 divisors (see below), whose sum is σ = 24047304624. Its totient is φ = 14231715840.

The previous prime is 18913808401. The next prime is 18913808411. The reversal of 18913808405 is 50480831981.

It can be written as a sum of positive squares in 8 ways, for example, as 131928196 + 18781880209 = 11486^2 + 137047^2 .

It is not a de Polignac number, because 18913808405 - 2² = 18913808401 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18913808405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18913808401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60365 + ... + 203645.

It is an arithmetic number, because the mean of its divisors is an integer number (1502956539).

Almost surely, 2^18913808405 is an apocalyptic number.

It is an amenable number.

18913808405 is a deficient number, since it is larger than the sum of its proper divisors (5133496219).

18913808405 is a wasteful number, since it uses less digits than its factorization.

18913808405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144856.

The product of its (nonzero) digits is 276480, while the sum is 47.

The spelling of 18913808405 in words is "eighteen billion, nine hundred thirteen million, eight hundred eight thousand, four hundred five".