1816381801836 has 288 divisors, whose sum is σ = 5660942031360. Its totient is φ = 501872112000.

The previous prime is 1816381801771. The next prime is 1816381801841. The reversal of 1816381801836 is 6381081836181.

1816381801836 is a `hidden beast` number, since 1 + 8 + 1 + 6 + 381 + 80 + 183 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 22943641 + ... + 23022671.

It is an arithmetic number, because the mean of its divisors is an integer number (19656048720).

Almost surely, 2^{1816381801836} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1816381801836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2830471015680).

1816381801836 is an abundant number, since it is smaller than the sum of its proper divisors (3844560229524).

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

1816381801836 is a wasteful number, since it uses less digits than its factorization.

1816381801836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79202 (or 79187 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 54.

The spelling of 1816381801836 in words is "one trillion, eight hundred sixteen billion, three hundred eighty-one million, eight hundred one thousand, eight hundred thirty-six".