221045400 has 144 divisors (see below), whose sum is σ = 762637200. Its totient is φ = 57335040.

The previous prime is 221045399. The next prime is 221045417. The reversal of 221045400 is 4540122.

221045400 is a `hidden beast` number, since 2 + 210 + 454 + 0 + 0 = 666.

221045400 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221045400² = 97722137722320000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 64941 + ... + 68259.

Almost surely, 2^221045400 is an apocalyptic number.

221045400 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 221045400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (381318600).

221045400 is an abundant number, since it is smaller than the sum of its proper divisors (541591800).

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

221045400 is a wasteful number, since it uses less digits than its factorization.

221045400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3378 (or 3366 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 221045400 is about 14867.5956361478. The cubic root of 221045400 is about 604.6357573457.

Adding to 221045400 its reverse (4540122), we get a palindrome (225585522).

It can be divided in two parts, 221045 and 400, that added together give a triangular number (221445 = T₆₆₅).

The spelling of 221045400 in words is "two hundred twenty-one million, forty-five thousand, four hundred".