221491827648 has 1120 divisors, whose sum is σ = 845130908160. Its totient is φ = 55808040960.

The previous prime is 221491827643. The next prime is 221491827679. The reversal of 221491827648 is 846728194122.

221491827648 is a `hidden beast` number, since 2 + 2 + 1 + 491 + 82 + 76 + 4 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 221491827594 and 221491827603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221491827643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1237384423 + ... + 1237384601.

It is an arithmetic number, because the mean of its divisors is an integer number (754581168).

Almost surely, 2^221491827648 is an apocalyptic number.

221491827648 is a gapful number since it is divisible by the number (28) 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 221491827648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (422565454080).

221491827648 is an abundant number, since it is smaller than the sum of its proper divisors (623639080512).

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

221491827648 is a wasteful number, since it uses less digits than its factorization.

221491827648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327 (or 308 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 54.

The spelling of 221491827648 in words is "two hundred twenty-one billion, four hundred ninety-one million, eight hundred twenty-seven thousand, six hundred forty-eight".