1221121111220 has 48 divisors (see below), whose sum is σ = 2591477188608. Its totient is φ = 483302816640.

The previous prime is 1221121111219. The next prime is 1221121111277. The reversal of 1221121111220 is 221111211221.

It is a super-2 number, since 2×1221121111220² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 302975 + ... + 1591865.

It is an arithmetic number, because the mean of its divisors is an integer number (53989108096).

Almost surely, 2^{1221121111220} is an apocalyptic number.

1221121111220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221121111220 is an abundant number, since it is smaller than the sum of its proper divisors (1370356077388).

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

1221121111220 is a wasteful number, since it uses less digits than its factorization.

1221121111220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1289400 (or 1289398 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1221121111220 its reverse (221111211221), we get a palindrome (1442232322441).

The spelling of 1221121111220 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twenty".