1221200122021 has 4 divisors (see below), whose sum is σ = 1332218314944. Its totient is φ = 1110181929100.

The previous prime is 1221200122003. The next prime is 1221200122033. The reversal of 1221200122021 is 1202210021221.

It is a happy number.

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 1221200122021 - 2⁷ = 1221200121893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221200121986 and 1221200122004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221200122001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55509096445 + ... + 55509096466.

It is an arithmetic number, because the mean of its divisors is an integer number (333054578736).

Almost surely, 2^{1221200122021} is an apocalyptic number.

1221200122021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221200122021 is a deficient number, since it is larger than the sum of its proper divisors (111018192923).

1221200122021 is a wasteful number, since it uses less digits than its factorization.

1221200122021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111018192922.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 1221200122021 its reverse (1202210021221), we get a palindrome (2423410143242).

The spelling of 1221200122021 in words is "one trillion, two hundred twenty-one billion, two hundred million, one hundred twenty-two thousand, twenty-one".