18021560400 has 360 divisors, whose sum is σ = 66622270624. Its totient is φ = 4674931200.

The previous prime is 18021560383. The next prime is 18021560411. The reversal of 18021560400 is 406512081.

18021560400 is a `hidden beast` number, since 1 + 80 + 21 + 560 + 4 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3593895 + ... + 3598905.

Almost surely, 2^18021560400 is an apocalyptic number.

18021560400 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 18021560400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33311135312).

18021560400 is an abundant number, since it is smaller than the sum of its proper divisors (48600710224).

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

18021560400 is a wasteful number, since it uses less digits than its factorization.

18021560400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5081 (or 5058 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The spelling of 18021560400 in words is "eighteen billion, twenty-one million, five hundred sixty thousand, four hundred".