221211400 has 96 divisors (see below), whose sum is σ = 537856200. Its totient is φ = 84531200.

The previous prime is 221211383. The next prime is 221211407. The reversal of 221211400 is 4112122.

It is a happy number.

221211400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 12 ways, for example, as 13793796 + 207417604 = 3714^2 + 14402^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221211407) 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, 434346 + ... + 434854.

Almost surely, 2^221211400 is an apocalyptic number.

221211400 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 221211400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (268928100).

221211400 is an abundant number, since it is smaller than the sum of its proper divisors (316644800).

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

221211400 is a wasteful number, since it uses less digits than its factorization.

221211400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619 (or 610 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 221211400 is about 14873.1771992402. The cubic root of 221211400 is about 604.7870753119.

Adding to 221211400 its reverse (4112122), we get a palindrome (225323522).

The spelling of 221211400 in words is "two hundred twenty-one million, two hundred eleven thousand, four hundred".