1821204836400 has 60 divisors (see below), whose sum is σ = 5833926163112. Its totient is φ = 485654622720.

The previous prime is 1821204836393. The next prime is 1821204836447. The reversal of 1821204836400 is 46384021281.

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×1821204836400² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 758834149 + ... + 758836548.

Almost surely, 2^{1821204836400} is an apocalyptic number.

1821204836400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1821204836400 is an abundant number, since it is smaller than the sum of its proper divisors (4012721326712).

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

1821204836400 is a wasteful number, since it uses less digits than its factorization.

1821204836400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1517670718 (or 1517670707 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 39.

Adding to 1821204836400 its reverse (46384021281), we get a palindrome (1867588857681).

The spelling of 1821204836400 in words is "one trillion, eight hundred twenty-one billion, two hundred four million, eight hundred thirty-six thousand, four hundred".