11661618211200 has 336 divisors, whose sum is σ = 43192012031700. Its totient is φ = 3109764234240.

The previous prime is 11661618211153. The next prime is 11661618211207. The reversal of 11661618211200 is 211281616611.

11661618211200 is a `hidden beast` number, since 1 + 1 + 6 + 6 + 1 + 618 + 2 + 11 + 20 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11661618211207) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 166690 + ... + 4832289.

Almost surely, 2^{11661618211200} is an apocalyptic number.

11661618211200 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 11661618211200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21596006015850).

11661618211200 is an abundant number, since it is smaller than the sum of its proper divisors (31530393820500).

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

11661618211200 is an frugal number, since it uses more digits than its factorization.

11661618211200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4999021 (or 4998989 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

Adding to 11661618211200 its reverse (211281616611), we get a palindrome (11872899827811).

The spelling of 11661618211200 in words is "eleven trillion, six hundred sixty-one billion, six hundred eighteen million, two hundred eleven thousand, two hundred".