1221221110021 has 8 divisors (see below), whose sum is σ = 1334976825024. Its totient is φ = 1107921330720.

The previous prime is 1221221110009. The next prime is 1221221110027. The reversal of 1221221110021 is 1200111221221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221221110021 - 2⁵ = 1221221109989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221221109977 and 1221221110004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221110027) 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, 113978320 + ... + 113989033.

It is an arithmetic number, because the mean of its divisors is an integer number (166872103128).

Almost surely, 2^{1221221110021} is an apocalyptic number.

1221221110021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221221110021 is a deficient number, since it is larger than the sum of its proper divisors (113755715003).

1221221110021 is a wasteful number, since it uses less digits than its factorization.

1221221110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227967851.

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

Adding to 1221221110021 its reverse (1200111221221), we get a palindrome (2421332331242).

The spelling of 1221221110021 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred ten thousand, twenty-one".