1221130203821 has 4 divisors (see below), whose sum is σ = 1332142040544. Its totient is φ = 1110118367100.

The previous prime is 1221130203773. The next prime is 1221130203829. The reversal of 1221130203821 is 1283020311221.

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 1221130203821 - 2¹⁸ = 1221129941677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221130203829) 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, 55505918345 + ... + 55505918366.

It is an arithmetic number, because the mean of its divisors is an integer number (333035510136).

Almost surely, 2^{1221130203821} is an apocalyptic number.

1221130203821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221130203821 is a deficient number, since it is larger than the sum of its proper divisors (111011836723).

1221130203821 is a wasteful number, since it uses less digits than its factorization.

1221130203821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111011836722.

The product of its (nonzero) digits is 1152, while the sum is 26.

The spelling of 1221130203821 in words is "one trillion, two hundred twenty-one billion, one hundred thirty million, two hundred three thousand, eight hundred twenty-one".