1221551111022 has 64 divisors (see below), whose sum is σ = 2812141290240. Its totient is φ = 349851398400.

The previous prime is 1221551110991. The next prime is 1221551111047. The reversal of 1221551111022 is 2201111551221.

It is a junction number, because it is equal to n+sod(n) for n = 1221551110983 and 1221551111001.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 628983 + ... + 1684850.

It is an arithmetic number, because the mean of its divisors is an integer number (43939707660).

Almost surely, 2^{1221551111022} is an apocalyptic number.

1221551111022 is an abundant number, since it is smaller than the sum of its proper divisors (1590590179218).

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

1221551111022 is a wasteful number, since it uses less digits than its factorization.

1221551111022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2314289.

The product of its (nonzero) digits is 400, while the sum is 24.

Adding to 1221551111022 its reverse (2201111551221), we get a palindrome (3422662662243).

The spelling of 1221551111022 in words is "one trillion, two hundred twenty-one billion, five hundred fifty-one million, one hundred eleven thousand, twenty-two".