1223156121 has 16 divisors (see below), whose sum is σ = 1804197888. Its totient is φ = 730864400.

The previous prime is 1223156117. The next prime is 1223156149. The reversal of 1223156121 is 1216513221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1223156121 - 2² = 1223156117 is a prime.

It is a super-2 number, since 2×1223156121² = 2992221792679533282, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1223156091 and 1223156100.

It is not an unprimeable number, because it can be changed into a prime (1223156161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 258681 + ... + 263366.

It is an arithmetic number, because the mean of its divisors is an integer number (112762368).

Almost surely, 2^1223156121 is an apocalyptic number.

1223156121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1223156121 is a deficient number, since it is larger than the sum of its proper divisors (581041767).

1223156121 is a wasteful number, since it uses less digits than its factorization.

1223156121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522132.

The product of its digits is 720, while the sum is 24.

The square root of 1223156121 is about 34973.6489517465. The cubic root of 1223156121 is about 1069.4503599766.

Adding to 1223156121 its reverse (1216513221), we get a palindrome (2439669342).

The spelling of 1223156121 in words is "one billion, two hundred twenty-three million, one hundred fifty-six thousand, one hundred twenty-one".