1221210101221 has 16 divisors (see below), whose sum is σ = 1374045596928. Its totient is φ = 1075811752000.

The previous prime is 1221210101213. The next prime is 1221210101227. The reversal of 1221210101221 is 1221010121221.

It is a cyclic number.

It is not a de Polignac number, because 1221210101221 - 2³ = 1221210101213 is a prime.

It is a super-2 number, since 2×1221210101221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221210101195 and 1221210101204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221210101227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11641390 + ... + 11745823.

It is an arithmetic number, because the mean of its divisors is an integer number (85877849808).

Almost surely, 2^{1221210101221} is an apocalyptic number.

1221210101221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221210101221 is a deficient number, since it is larger than the sum of its proper divisors (152835495707).

1221210101221 is a wasteful number, since it uses less digits than its factorization.

1221210101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23387372.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221210101221 its reverse (1221010121221), we get a palindrome (2442220222442).

The spelling of 1221210101221 in words is "one trillion, two hundred twenty-one billion, two hundred ten million, one hundred one thousand, two hundred twenty-one".