18444427155 has 48 divisors (see below), whose sum is σ = 39859133184. Its totient is φ = 7665215040.

The previous prime is 18444427153. The next prime is 18444427159. The reversal of 18444427155 is 55172444481.

18444427155 is a `hidden beast` number, since 18 + 44 + 442 + 7 + 155 = 666.

It is not a de Polignac number, because 18444427155 - 2¹ = 18444427153 is a prime.

It is a super-2 number, since 2×18444427155² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 18444427155.

It is not an unprimeable number, because it can be changed into a prime (18444427153) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2658069 + ... + 2664998.

It is an arithmetic number, because the mean of its divisors is an integer number (830398608).

Almost surely, 2^18444427155 is an apocalyptic number.

18444427155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

18444427155 is an abundant number, since it is smaller than the sum of its proper divisors (21414706029).

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

18444427155 is a wasteful number, since it uses less digits than its factorization.

18444427155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5323096 (or 5323093 counting only the distinct ones).

The product of its digits is 716800, while the sum is 45.

The spelling of 18444427155 in words is "eighteen billion, four hundred forty-four million, four hundred twenty-seven thousand, one hundred fifty-five".