1816381543824 has 105 divisors (see below), whose sum is σ = 5276867977243. Its totient is φ = 605411996256.

The previous prime is 1816381543789. The next prime is 1816381543841. The reversal of 1816381543824 is 4283451836181.

It is a happy number.

The square root of 1816381543824 is 1347732.

It is a perfect power (a square), and thus also a powerful number.

1816381543824 is a `hidden beast` number, since 1 + 8 + 16 + 3 + 8 + 1 + 543 + 82 + 4 = 666.

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

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 145548817 + ... + 145561295.

Almost surely, 2^{1816381543824} is an apocalyptic number.

1816381543824 is the 1347732-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1816381543824

1816381543824 is an abundant number, since it is smaller than the sum of its proper divisors (3460486433419).

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

1816381543824 is an frugal number, since it uses more digits than its factorization.

1816381543824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24984 (or 12484 counting only the distinct ones).

The product of its digits is 4423680, while the sum is 54.

The spelling of 1816381543824 in words is "one trillion, eight hundred sixteen billion, three hundred eighty-one million, five hundred forty-three thousand, eight hundred twenty-four".