1821525565440 has 448 divisors, whose sum is σ = 6676588892160. Its totient is φ = 415385518080.

The previous prime is 1821525565429. The next prime is 1821525565591. The reversal of 1821525565440 is 445655251281.

It is a tau number, because it is divible by the number of its divisors (448).

It is a hoax number, since the sum of its digits (48) 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 (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1821525565440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 412014430 + ... + 412018850.

Almost surely, 2^{1821525565440} is an apocalyptic number.

1821525565440 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 1821525565440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3338294446080).

1821525565440 is an abundant number, since it is smaller than the sum of its proper divisors (4855063326720).

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

1821525565440 is an equidigital number, since it uses as much as digits as its factorization.

1821525565440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4941 (or 4917 counting only the distinct ones).

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

The spelling of 1821525565440 in words is "one trillion, eight hundred twenty-one billion, five hundred twenty-five million, five hundred sixty-five thousand, four hundred forty".