18004561920 has 624 divisors, whose sum is σ = 67712965632. Its totient is φ = 4411883520.

The previous prime is 18004561907. The next prime is 18004561931. The reversal of 18004561920 is 2916540081.

18004561920 is a `hidden beast` number, since 1 + 8 + 0 + 0 + 4 + 561 + 92 + 0 = 666.

It is a super-2 number, since 2×18004561920² (a number of 21 digits) contains 22 as substring.

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

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 47 ways as a sum of consecutive naturals, for example, 131420092 + ... + 131420228.

It is an arithmetic number, because the mean of its divisors is an integer number (108514368).

Almost surely, 2^18004561920 is an apocalyptic number.

18004561920 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 18004561920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33856482816).

18004561920 is an abundant number, since it is smaller than the sum of its proper divisors (49708403712).

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

18004561920 is a wasteful number, since it uses less digits than its factorization.

18004561920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 18004561920 in words is "eighteen billion, four million, five hundred sixty-one thousand, nine hundred twenty".