221356640 has 24 divisors (see below), whose sum is σ = 522955440. Its totient is φ = 88542592.

The previous prime is 221356637. The next prime is 221356651. The reversal of 221356640 is 46653122.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 691580 + ... + 691899.

It is an arithmetic number, because the mean of its divisors is an integer number (21789810).

Almost surely, 2^221356640 is an apocalyptic number.

221356640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221356640 is an abundant number, since it is smaller than the sum of its proper divisors (301598800).

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

221356640 is a wasteful number, since it uses less digits than its factorization.

221356640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1383494 (or 1383486 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 221356640 is about 14878.0590131912. The cubic root of 221356640 is about 604.9194073372.

The spelling of 221356640 in words is "two hundred twenty-one million, three hundred fifty-six thousand, six hundred forty".