18420517440 has 672 divisors, whose sum is σ = 71893785600. Its totient is φ = 4297605120.

The previous prime is 18420517429. The next prime is 18420517459. The reversal of 18420517440 is 4471502481.

It is a happy number.

18420517440 is a `hidden beast` number, since 1 + 8 + 4 + 205 + 1 + 7 + 440 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18420517395 and 18420517404.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 68477626 + ... + 68477894.

It is an arithmetic number, because the mean of its divisors is an integer number (106984800).

Almost surely, 2^18420517440 is an apocalyptic number.

18420517440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18420517440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35946892800).

18420517440 is an abundant number, since it is smaller than the sum of its proper divisors (53473268160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18420517440 is a wasteful number, since it uses less digits than its factorization.

18420517440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395 (or 382 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 36.

The spelling of 18420517440 in words is "eighteen billion, four hundred twenty million, five hundred seventeen thousand, four hundred forty".