221555424 has 48 divisors (see below), whose sum is σ = 615798288. Its totient is φ = 69507072.

The previous prime is 221555363. The next prime is 221555461. The reversal of 221555424 is 424555122.

221555424 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (48).

It is a junction number, because it is equal to n+sod(n) for n = 221555391 and 221555400.

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 7 ways as a sum of consecutive naturals, for example, 66247 + ... + 69510.

It is an arithmetic number, because the mean of its divisors is an integer number (12829131).

Almost surely, 2^221555424 is an apocalyptic number.

221555424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

221555424 is an abundant number, since it is smaller than the sum of its proper divisors (394242864).

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

221555424 is a wasteful number, since it uses less digits than its factorization.

221555424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135787 (or 135779 counting only the distinct ones).

The product of its digits is 16000, while the sum is 30.

The square root of 221555424 is about 14884.7379553689. The cubic root of 221555424 is about 605.1004309289.

The spelling of 221555424 in words is "two hundred twenty-one million, five hundred fifty-five thousand, four hundred twenty-four".