1821153554544 has 160 divisors (see below), whose sum is σ = 5059965570048. Its totient is φ = 563092992000.

The previous prime is 1821153554531. The next prime is 1821153554551. The reversal of 1821153554544 is 4454553511281.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a junction number, because it is equal to n+sod(n) for n = 1821153554493 and 1821153554502.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4590984 + ... + 4971864.

Almost surely, 2^{1821153554544} 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 1821153554544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2529982785024).

1821153554544 is an abundant number, since it is smaller than the sum of its proper divisors (3238812015504).

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

1821153554544 is a wasteful number, since it uses less digits than its factorization.

1821153554544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381047 (or 381041 counting only the distinct ones).

The product of its digits is 1920000, while the sum is 48.

The spelling of 1821153554544 in words is "one trillion, eight hundred twenty-one billion, one hundred fifty-three million, five hundred fifty-four thousand, five hundred forty-four".