18091563840 has 504 divisors, whose sum is σ = 73908586752. Its totient is φ = 4131855360.

The previous prime is 18091563803. The next prime is 18091563869. The reversal of 18091563840 is 4836519081.

18091563840 is a `hidden beast` number, since 1 + 8 + 0 + 9 + 1 + 5 + 638 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

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

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, 14696025 + ... + 14697255.

Almost surely, 2^18091563840 is an apocalyptic number.

18091563840 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 18091563840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36954293376).

18091563840 is an abundant number, since it is smaller than the sum of its proper divisors (55817022912).

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

18091563840 is an frugal number, since it uses more digits than its factorization.

18091563840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1279 (or 1248 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 18091563840 in words is "eighteen billion, ninety-one million, five hundred sixty-three thousand, eight hundred forty".