221549261568 has 144 divisors (see below), whose sum is σ = 624700492416. Its totient is φ = 69464309760.

The previous prime is 221549261567. The next prime is 221549261611. The reversal of 221549261568 is 865162945122.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 221549261568.

It is not an unprimeable number, because it can be changed into a prime (221549261567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27818355 + ... + 27826317.

It is an arithmetic number, because the mean of its divisors is an integer number (4338197864).

Almost surely, 2^221549261568 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 221549261568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (312350246208).

221549261568 is an abundant number, since it is smaller than the sum of its proper divisors (403151230848).

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

221549261568 is a wasteful number, since it uses less digits than its factorization.

221549261568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10130 (or 10116 counting only the distinct ones).

The product of its digits is 2073600, while the sum is 51.

The spelling of 221549261568 in words is "two hundred twenty-one billion, five hundred forty-nine million, two hundred sixty-one thousand, five hundred sixty-eight".