11991997555200 has 960 divisors, whose sum is σ = 47777862021120. Its totient is φ = 2928493854720.

The previous prime is 11991997555199. The next prime is 11991997555201. The reversal of 11991997555200 is 255579919911.

11991997555200 is a `hidden beast` number, since 1 + 1 + 9 + 9 + 1 + 9 + 9 + 75 + 552 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (11991997555199) and next prime (11991997555201).

It is a tau number, because it is divible by the number of its divisors (960).

It is not an unprimeable number, because it can be changed into a prime (11991997555201) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 570575092 + ... + 570596108.

It is an arithmetic number, because the mean of its divisors is an integer number (49768606272).

Almost surely, 2^{11991997555200} is an apocalyptic number.

11991997555200 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 11991997555200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23888931010560).

11991997555200 is an abundant number, since it is smaller than the sum of its proper divisors (35785864465920).

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

11991997555200 is a wasteful number, since it uses less digits than its factorization.

11991997555200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21194 (or 21167 counting only the distinct ones).

The product of its (nonzero) digits is 11481750, while the sum is 63.

The spelling of 11991997555200 in words is "eleven trillion, nine hundred ninety-one billion, nine hundred ninety-seven million, five hundred fifty-five thousand, two hundred".