221555400 has 96 divisors (see below), whose sum is σ = 749282400. Its totient is φ = 53708800.

The previous prime is 221555363. The next prime is 221555461. The reversal of 221555400 is 4555122.

It is a happy number.

It is a super-3 number, since 3×221555400³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

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 23 ways as a sum of consecutive naturals, for example, 10185 + ... + 23384.

It is an arithmetic number, because the mean of its divisors is an integer number (7805025).

Almost surely, 2^221555400 is an apocalyptic number.

221555400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221555400 is an abundant number, since it is smaller than the sum of its proper divisors (527727000).

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

221555400 is a wasteful number, since it uses less digits than its factorization.

221555400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33599 (or 33590 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 24.

The square root of 221555400 is about 14884.7371491740. The cubic root of 221555400 is about 605.1004090797.

The spelling of 221555400 in words is "two hundred twenty-one million, five hundred fifty-five thousand, four hundred".