1221101023 has 4 divisors (see below), whose sum is σ = 1221192928. Its totient is φ = 1221009120.

The previous prime is 1221101017. The next prime is 1221101059. The reversal of 1221101023 is 3201011221.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 3201011221 = 7541 ⋅424481.

It is a cyclic number.

It is not a de Polignac number, because 1221101023 - 2⁹ = 1221100511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221100994 and 1221101012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221101083) 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, 21786 + ... + 54007.

It is an arithmetic number, because the mean of its divisors is an integer number (305298232).

Almost surely, 2^1221101023 is an apocalyptic number.

1221101023 is a deficient number, since it is larger than the sum of its proper divisors (91905).

1221101023 is an equidigital number, since it uses as much as digits as its factorization.

1221101023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91904.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1221101023 is about 34944.2559371351. The cubic root of 1221101023 is about 1068.8510749773.

Adding to 1221101023 its reverse (3201011221), we get a palindrome (4422112244).

The spelling of 1221101023 in words is "one billion, two hundred twenty-one million, one hundred one thousand, twenty-three".