1221631185600 has 1008 divisors, whose sum is σ = 5155192713216. Its totient is φ = 268489728000.

The previous prime is 1221631185571. The next prime is 1221631185611. The reversal of 1221631185600 is 65811361221.

1221631185600 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 6 + 31 + 18 + 5 + 600 = 666.

It is a tau number, because it is divible by the number of its divisors (1008).

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

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 521840430 + ... + 521842770.

Almost surely, 2^{1221631185600} is an apocalyptic number.

1221631185600 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 1221631185600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2577596356608).

1221631185600 is an abundant number, since it is smaller than the sum of its proper divisors (3933561527616).

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

1221631185600 is a wasteful number, since it uses less digits than its factorization.

1221631185600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2574 (or 2556 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 1221631185600 in words is "one trillion, two hundred twenty-one billion, six hundred thirty-one million, one hundred eighty-five thousand, six hundred".