221221213440 has 144 divisors (see below), whose sum is σ = 743711035200. Its totient is φ = 55887446016.

The previous prime is 221221213373. The next prime is 221221213501. The reversal of 221221213440 is 44312122122.

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

It is a self number, because there is not a number n which added to its sum of digits gives 221221213440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1443085 + ... + 1589004.

Almost surely, 2^221221213440 is an apocalyptic number.

221221213440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221221213440 is an abundant number, since it is smaller than the sum of its proper divisors (522489821760).

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

221221213440 is a wasteful number, since it uses less digits than its factorization.

221221213440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3032132 (or 3032118 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 221221213440 its reverse (44312122122), we get a palindrome (265533335562).

The spelling of 221221213440 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred thirteen thousand, four hundred forty".