1221100220121 has 8 divisors (see below), whose sum is σ = 1723906193184. Its totient is φ = 766180530240.

The previous prime is 1221100220113. The next prime is 1221100220167. The reversal of 1221100220121 is 1210220011221.

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

It is not a de Polignac number, because 1221100220121 - 2³ = 1221100220113 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221100220121.

It is not an unprimeable number, because it can be changed into a prime (1221100230121) 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, 11971570735 + ... + 11971570836.

It is an arithmetic number, because the mean of its divisors is an integer number (215488274148).

Almost surely, 2^{1221100220121} is an apocalyptic number.

It is an amenable number.

1221100220121 is a deficient number, since it is larger than the sum of its proper divisors (502805973063).

1221100220121 is a wasteful number, since it uses less digits than its factorization.

1221100220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23943141591.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1221100220121 its reverse (1210220011221), we get a palindrome (2431320231342).

The spelling of 1221100220121 in words is "one trillion, two hundred twenty-one billion, one hundred million, two hundred twenty thousand, one hundred twenty-one".