221530400 has 288 divisors, whose sum is σ = 708704640. Its totient is φ = 65617920.

The previous prime is 221530381. The next prime is 221530447. The reversal of 221530400 is 4035122.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1237511 + ... + 1237689.

It is an arithmetic number, because the mean of its divisors is an integer number (2460780).

Almost surely, 2^221530400 is an apocalyptic number.

221530400 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 221530400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (354352320).

221530400 is an abundant number, since it is smaller than the sum of its proper divisors (487174240).

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

221530400 is a wasteful number, since it uses less digits than its factorization.

221530400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 221530400 is about 14883.8973390708. The cubic root of 221530400 is about 605.0776486636.

Adding to 221530400 its reverse (4035122), we get a palindrome (225565522).

The spelling of 221530400 in words is "two hundred twenty-one million, five hundred thirty thousand, four hundred".