1221010020221 has 8 divisors (see below), whose sum is σ = 1233151078104. Its totient is φ = 1208869979200.

The previous prime is 1221010020203. The next prime is 1221010020271. The reversal of 1221010020221 is 1220200101221.

It can be written as a sum of positive squares in 4 ways, for example, as 1171403594596 + 49606425625 = 1082314^2 + 222725^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221010020221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221010020196 and 1221010020205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221010020271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2284655 + ... + 2767971.

It is an arithmetic number, because the mean of its divisors is an integer number (154143884763).

Almost surely, 2^{1221010020221} is an apocalyptic number.

It is an amenable number.

1221010020221 is a deficient number, since it is larger than the sum of its proper divisors (12141057883).

1221010020221 is a wasteful number, since it uses less digits than its factorization.

1221010020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508431.

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

Adding to 1221010020221 its reverse (1220200101221), we get a palindrome (2441210121442).

The spelling of 1221010020221 in words is "one trillion, two hundred twenty-one billion, ten million, twenty thousand, two hundred twenty-one".