221221222121220 has 72 divisors (see below), whose sum is σ = 641515239753024. Its totient is φ = 56958107751552.

The previous prime is 221221222121219. The next prime is 221221222121239. The reversal of 221221222121220 is 22121222122122.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2191994944 + ... + 2192095863.

Almost surely, 2^{221221222121220} is an apocalyptic number.

221221222121220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221221222121220 is an abundant number, since it is smaller than the sum of its proper divisors (420294017631804).

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

221221222121220 is a wasteful number, since it uses less digits than its factorization.

221221222121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4384090877 (or 4384090846 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 24.

Adding to 221221222121220 its reverse (22121222122122), we get a palindrome (243342444243342).

The spelling of 221221222121220 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, two hundred twenty-two million, one hundred twenty-one thousand, two hundred twenty".