221645220 has 48 divisors (see below), whose sum is σ = 635046720. Its totient is φ = 57730176.

The previous prime is 221645219. The next prime is 221645251. The reversal of 221645220 is 22546122.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40375 + ... + 45534.

It is an arithmetic number, because the mean of its divisors is an integer number (13230140).

Almost surely, 2^221645220 is an apocalyptic number.

221645220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221645220 is an abundant number, since it is smaller than the sum of its proper divisors (413401500).

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

221645220 is a wasteful number, since it uses less digits than its factorization.

221645220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85964 (or 85962 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 221645220 is about 14887.7540280594. The cubic root of 221645220 is about 605.1821685791.

The spelling of 221645220 in words is "two hundred twenty-one million, six hundred forty-five thousand, two hundred twenty".