221640000 has 140 divisors (see below), whose sum is σ = 733190304. Its totient is φ = 59072000.

The previous prime is 221639989. The next prime is 221640007. The reversal of 221640000 is 46122.

221640000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221640007) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 119077 + ... + 120923.

Almost surely, 2^221640000 is an apocalyptic number.

221640000 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 221640000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (366595152).

221640000 is an abundant number, since it is smaller than the sum of its proper divisors (511550304).

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

221640000 is an equidigital number, since it uses as much as digits as its factorization.

221640000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1882 (or 1857 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 221640000 is about 14887.5787151571. The cubic root of 221640000 is about 605.1774176296.

Adding to 221640000 its reverse (46122), we get a palindrome (221686122).

The spelling of 221640000 in words is "two hundred twenty-one million, six hundred forty thousand".