1221331011021 has 24 divisors (see below), whose sum is σ = 1990884411360. Its totient is φ = 714676452000.

The previous prime is 1221331011007. The next prime is 1221331011031. The reversal of 1221331011021 is 1201101331221.

1221331011021 is a `hidden beast` number, since 1 + 221 + 3 + 310 + 110 + 21 = 666.

It is not a de Polignac number, because 1221331011021 - 2⁵ = 1221331010989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221331010985 and 1221331011003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221331011031) 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 23 ways as a sum of consecutive naturals, for example, 212698455 + ... + 212704196.

It is an arithmetic number, because the mean of its divisors is an integer number (82953517140).

Almost surely, 2^{1221331011021} is an apocalyptic number.

1221331011021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221331011021 is a deficient number, since it is larger than the sum of its proper divisors (769553400339).

1221331011021 is a wasteful number, since it uses less digits than its factorization.

1221331011021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425402697 (or 425402694 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

Adding to 1221331011021 its reverse (1201101331221), we get a palindrome (2422432342242).

The spelling of 1221331011021 in words is "one trillion, two hundred twenty-one billion, three hundred thirty-one million, eleven thousand, twenty-one".