1821551846400 has 1320 divisors, whose sum is σ = 7925476737024. Its totient is φ = 407553638400.

The previous prime is 1821551846399. The next prime is 1821551846407. The reversal of 1821551846400 is 46481551281.

1821551846400 is a `hidden beast` number, since 1 + 82 + 15 + 518 + 4 + 6 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1320).

It is a super-2 number, since 2×1821551846400² (a number of 25 digits) contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (1821551846407) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 296521729 + ... + 296527871.

Almost surely, 2^{1821551846400} is an apocalyptic number.

1821551846400 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 1821551846400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3962738368512).

1821551846400 is an abundant number, since it is smaller than the sum of its proper divisors (6103924890624).

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

1821551846400 is a wasteful number, since it uses less digits than its factorization.

1821551846400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6209 (or 6177 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 45.

The spelling of 1821551846400 in words is "one trillion, eight hundred twenty-one billion, five hundred fifty-one million, eight hundred forty-six thousand, four hundred".