221918957568 has 624 divisors, whose sum is σ = 821183266176. Its totient is φ = 56056872960.

The previous prime is 221918957461. The next prime is 221918957587. The reversal of 221918957568 is 865759819122.

221918957568 is a `hidden beast` number, since 2 + 2 + 1 + 9 + 18 + 9 + 57 + 568 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 105024480 + ... + 105026592.

It is an arithmetic number, because the mean of its divisors is an integer number (1315998824).

Almost surely, 2^221918957568 is an apocalyptic number.

221918957568 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 221918957568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (410591633088).

221918957568 is an abundant number, since it is smaller than the sum of its proper divisors (599264308608).

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

221918957568 is a wasteful number, since it uses less digits than its factorization.

221918957568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2198 (or 2173 counting only the distinct ones).

The product of its digits is 21772800, while the sum is 63.

The spelling of 221918957568 in words is "two hundred twenty-one billion, nine hundred eighteen million, nine hundred fifty-seven thousand, five hundred sixty-eight".