221655726720 has 1024 divisors, whose sum is σ = 884100096000. Its totient is φ = 52155187200.

The previous prime is 221655726679. The next prime is 221655726731. The reversal of 221655726720 is 27627556122.

221655726720 is a `hidden beast` number, since 2 + 2 + 1 + 6 + 5 + 572 + 6 + 72 + 0 = 666.

It is a super-2 number, since 2×221655726720² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 842797309 + ... + 842797571.

It is an arithmetic number, because the mean of its divisors is an integer number (863379000).

Almost surely, 2^221655726720 is an apocalyptic number.

221655726720 is a gapful number since it is divisible by the number (20) 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 221655726720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (442050048000).

221655726720 is an abundant number, since it is smaller than the sum of its proper divisors (662444369280).

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

221655726720 is a wasteful number, since it uses less digits than its factorization.

221655726720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478 (or 460 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 45.

The spelling of 221655726720 in words is "two hundred twenty-one billion, six hundred fifty-five million, seven hundred twenty-six thousand, seven hundred twenty".