221021336628 has 72 divisors (see below), whose sum is σ = 572510405376. Its totient is φ = 71852880000.

The previous prime is 221021336621. The next prime is 221021336663. The reversal of 221021336628 is 826633120122.

221021336628 is a `hidden beast` number, since 2 + 2 + 1 + 0 + 21 + 3 + 3 + 6 + 628 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 221021336592 and 221021336601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221021336621) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4704253 + ... + 4751003.

It is an arithmetic number, because the mean of its divisors is an integer number (7951533408).

Almost surely, 2^221021336628 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 221021336628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286255202688).

221021336628 is an abundant number, since it is smaller than the sum of its proper divisors (351489068748).

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

221021336628 is a wasteful number, since it uses less digits than its factorization.

221021336628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50005 (or 50000 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The spelling of 221021336628 in words is "two hundred twenty-one billion, twenty-one million, three hundred thirty-six thousand, six hundred twenty-eight".