1221122020221 has 24 divisors (see below), whose sum is σ = 1768759912920. Its totient is φ = 811812433536.

The previous prime is 1221122020177. The next prime is 1221122020249. The reversal of 1221122020221 is 1220202211221.

It is a happy number.

1221122020221 is a `hidden beast` number, since 1 + 221 + 1 + 220 + 2 + 0 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 33174615321 + 1187947404900 = 182139^2 + 1089930^2 .

It is not a de Polignac number, because 1221122020221 - 2⁹ = 1221122019709 is a prime.

It is a super-2 number, since 2×1221122020221² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221122020194 and 1221122020203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221122021221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 53932315 + ... + 53954951.

It is an arithmetic number, because the mean of its divisors is an integer number (73698329705).

Almost surely, 2^{1221122020221} is an apocalyptic number.

It is an amenable number.

1221122020221 is a deficient number, since it is larger than the sum of its proper divisors (547637892699).

1221122020221 is a wasteful number, since it uses less digits than its factorization.

1221122020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39085 (or 39082 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221122020221 its reverse (1220202211221), we get a palindrome (2441324231442).

It can be divided in two parts, 1221 and 122020221, that multiplied together give a palindrome (148986689841).

The spelling of 1221122020221 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-two million, twenty thousand, two hundred twenty-one".