221221244440 has 64 divisors (see below), whose sum is σ = 575246318400. Its totient is φ = 74995058688.

The previous prime is 221221244437. The next prime is 221221244449. The reversal of 221221244440 is 44442122122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 221221244399 and 221221244408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221244449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4413709 + ... + 4463548.

It is an arithmetic number, because the mean of its divisors is an integer number (8988223725).

Almost surely, 2^221221244440 is an apocalyptic number.

221221244440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221221244440 is an abundant number, since it is smaller than the sum of its proper divisors (354025073960).

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

221221244440 is a wasteful number, since it uses less digits than its factorization.

221221244440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8877364 (or 8877360 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 28.

Adding to 221221244440 its reverse (44442122122), we get a palindrome (265663366562).

The spelling of 221221244440 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred forty-four thousand, four hundred forty".