1221201001220 has 24 divisors (see below), whose sum is σ = 2564616859224. Its totient is φ = 488462351616.

The previous prime is 1221201001201. The next prime is 1221201001231. The reversal of 1221201001220 is 221001021221.

It can be written as a sum of positive squares in 4 ways, for example, as 379079101636 + 842121899584 = 615694^2 + 917672^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1221201001195 and 1221201001204.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 566417 + ... + 1662296.

It is an arithmetic number, because the mean of its divisors is an integer number (106859035801).

Almost surely, 2^{1221201001220} is an apocalyptic number.

1221201001220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221201001220 is an abundant number, since it is smaller than the sum of its proper divisors (1343415858004).

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

1221201001220 is a wasteful number, since it uses less digits than its factorization.

1221201001220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2256119 (or 2256117 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1221201001220 its reverse (221001021221), we get a palindrome (1442202022441).

The spelling of 1221201001220 in words is "one trillion, two hundred twenty-one billion, two hundred one million, one thousand, two hundred twenty".