1221122221021 has 4 divisors (see below), whose sum is σ = 1221127687872. Its totient is φ = 1221116754172.

The previous prime is 1221122221009. The next prime is 1221122221031. The reversal of 1221122221021 is 1201222211221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221122221021 - 2⁷ = 1221122220893 is a prime.

It is a super-2 number, since 2×1221122221021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221122221021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221122221031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2383435 + ... + 2850088.

It is an arithmetic number, because the mean of its divisors is an integer number (305281921968).

Almost surely, 2^{1221122221021} is an apocalyptic number.

It is an amenable number.

1221122221021 is a deficient number, since it is larger than the sum of its proper divisors (5466851).

1221122221021 is an equidigital number, since it uses as much as digits as its factorization.

1221122221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5466850.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1221122221021 its reverse (1201222211221), we get a palindrome (2422344432242).

The spelling of 1221122221021 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-two million, two hundred twenty-one thousand, twenty-one".