221491581696 has 864 divisors, whose sum is σ = 821465089536. Its totient is φ = 55738368000.

The previous prime is 221491581637. The next prime is 221491581743. The reversal of 221491581696 is 696185194122.

221491581696 is a `hidden beast` number, since 2 + 2 + 1 + 491 + 58 + 16 + 96 = 666.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 1049723031 + ... + 1049723241.

Almost surely, 2^221491581696 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221491581696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (410732544768).

221491581696 is an abundant number, since it is smaller than the sum of its proper divisors (599973507840).

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

221491581696 is a wasteful number, since it uses less digits than its factorization.

221491581696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 392 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The spelling of 221491581696 in words is "two hundred twenty-one billion, four hundred ninety-one million, five hundred eighty-one thousand, six hundred ninety-six".