18361405440 has 936 divisors, whose sum is σ = 78661121760. Its totient is φ = 3938844672.

The previous prime is 18361405367. The next prime is 18361405451. The reversal of 18361405440 is 4450416381.

18361405440 is a `hidden beast` number, since 18 + 3 + 61 + 40 + 544 + 0 = 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 = 18361405395 and 18361405404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 171601867 + ... + 171601973.

It is an arithmetic number, because the mean of its divisors is an integer number (84039660).

Almost surely, 2^18361405440 is an apocalyptic number.

18361405440 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 18361405440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39330560880).

18361405440 is an abundant number, since it is smaller than the sum of its proper divisors (60299716320).

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

18361405440 is a wasteful number, since it uses less digits than its factorization.

18361405440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

It can be divided in two parts, 18361 and 405440, that added together give a square (423801 = 651²).

The spelling of 18361405440 in words is "eighteen billion, three hundred sixty-one million, four hundred five thousand, four hundred forty".