18420517271550 has 96 divisors (see below), whose sum is σ = 46937698732512. Its totient is φ = 4777325498880.

The previous prime is 18420517271549. The next prime is 18420517271579. The reversal of 18420517271550 is 5517271502481.

It is a self number, because there is not a number n which added to its sum of digits gives 18420517271550.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12236832 + ... + 13659468.

It is an arithmetic number, because the mean of its divisors is an integer number (488934361797).

Almost surely, 2^{18420517271550} is an apocalyptic number.

18420517271550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18420517271550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23468849366256).

18420517271550 is an abundant number, since it is smaller than the sum of its proper divisors (28517181460962).

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

18420517271550 is a wasteful number, since it uses less digits than its factorization.

18420517271550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1425022 (or 1425017 counting only the distinct ones).

The product of its (nonzero) digits is 784000, while the sum is 48.

The spelling of 18420517271550 in words is "eighteen trillion, four hundred twenty billion, five hundred seventeen million, two hundred seventy-one thousand, five hundred fifty".