1221211212123 has 32 divisors (see below), whose sum is σ = 1864675768320. Its totient is φ = 696418007040.

The previous prime is 1221211211959. The next prime is 1221211212187. The reversal of 1221211212123 is 3212121121221.

It is not a de Polignac number, because 1221211212123 - 2⁸ = 1221211211867 is a prime.

It is a super-2 number, since 2×1221211212123² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 1221211212123.

It is not an unprimeable number, because it can be changed into a prime (1221211212223) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20672158 + ... + 20731148.

It is an arithmetic number, because the mean of its divisors is an integer number (58271117760).

Almost surely, 2^{1221211212123} is an apocalyptic number.

1221211212123 is a deficient number, since it is larger than the sum of its proper divisors (643464556197).

1221211212123 is a wasteful number, since it uses less digits than its factorization.

1221211212123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60987.

The product of its digits is 192, while the sum is 21.

Adding to 1221211212123 its reverse (3212121121221), we get a palindrome (4433332333344).

The spelling of 1221211212123 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twelve thousand, one hundred twenty-three".