1221503123 has 2 divisors, whose sum is σ = 1221503124. Its totient is φ = 1221503122.

The previous prime is 1221503111. The next prime is 1221503131. The reversal of 1221503123 is 3213051221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221503123 - 2¹⁰ = 1221502099 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221503095 and 1221503104.

It is not a weakly prime, because it can be changed into another prime (1221503183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610751561 + 610751562.

It is an arithmetic number, because the mean of its divisors is an integer number (610751562).

Almost surely, 2^1221503123 is an apocalyptic number.

1221503123 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221503123 is an equidigital number, since it uses as much as digits as its factorization.

1221503123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 1221503123 is about 34950.0089127313. The cubic root of 1221503123 is about 1068.9683838220.

Adding to 1221503123 its reverse (3213051221), we get a palindrome (4434554344).

The spelling of 1221503123 in words is "one billion, two hundred twenty-one million, five hundred three thousand, one hundred twenty-three".