221800656 has 120 divisors (see below), whose sum is σ = 727212384. Its totient is φ = 57603840.

The previous prime is 221800633. The next prime is 221800679. The reversal of 221800656 is 656008122.

It is an interprime number because it is at equal distance from previous prime (221800633) and next prime (221800679).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21586 + ... + 30158.

Almost surely, 2^221800656 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 221800656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (363606192).

221800656 is an abundant number, since it is smaller than the sum of its proper divisors (505411728).

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

221800656 is a wasteful number, since it uses less digits than its factorization.

221800656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8609 (or 8596 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 221800656 is about 14892.9733767304. The cubic root of 221800656 is about 605.3236034886.

Adding to 221800656 its reverse (656008122), we get a palindrome (877808778).

The spelling of 221800656 in words is "two hundred twenty-one million, eight hundred thousand, six hundred fifty-six".