1221123212123 has 4 divisors (see below), whose sum is σ = 1221263370408. Its totient is φ = 1220983053840.

The previous prime is 1221123212119. The next prime is 1221123212143. The reversal of 1221123212123 is 3212123211221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221123212123 - 2² = 1221123212119 is a prime.

It is a super-2 number, since 2×1221123212123² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221123212143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70066073 + ... + 70083498.

It is an arithmetic number, because the mean of its divisors is an integer number (305315842602).

Almost surely, 2^{1221123212123} is an apocalyptic number.

1221123212123 is a deficient number, since it is larger than the sum of its proper divisors (140158285).

1221123212123 is an equidigital number, since it uses as much as digits as its factorization.

1221123212123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140158284.

The product of its digits is 576, while the sum is 23.

Adding to 1221123212123 its reverse (3212123211221), we get a palindrome (4433246423344).

The spelling of 1221123212123 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-three million, two hundred twelve thousand, one hundred twenty-three".