221020400 has 60 divisors (see below), whose sum is σ = 562254192. Its totient is φ = 83205120.

The previous prime is 221020399. The next prime is 221020403. The reversal of 221020400 is 4020122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221020403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9452 + ... + 23051.

Almost surely, 2^221020400 is an apocalyptic number.

221020400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221020400 is an abundant number, since it is smaller than the sum of its proper divisors (341233792).

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

221020400 is a wasteful number, since it uses less digits than its factorization.

221020400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32538 (or 32527 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 221020400 is about 14866.7548577354. The cubic root of 221020400 is about 604.6129619323.

Adding to 221020400 its reverse (4020122), we get a palindrome (225040522).

The spelling of 221020400 in words is "two hundred twenty-one million, twenty thousand, four hundred".