1221111523 has 2 divisors, whose sum is σ = 1221111524. Its totient is φ = 1221111522.

The previous prime is 1221111511. The next prime is 1221111533. The reversal of 1221111523 is 3251111221.

It is a strong prime.

It is an emirp because it is prime and its reverse (3251111221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221111523 - 2⁵ = 1221111491 is a prime.

It is a super-2 number, since 2×1221111523² = 2982226703206759058, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221111523.

It is not a weakly prime, because it can be changed into another prime (1221111533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610555761 + 610555762.

It is an arithmetic number, because the mean of its divisors is an integer number (610555762).

Almost surely, 2^1221111523 is an apocalyptic number.

1221111523 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221111523 is an equidigital number, since it uses as much as digits as its factorization.

1221111523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120, while the sum is 19.

The square root of 1221111523 is about 34944.4061760963. The cubic root of 1221111523 is about 1068.8541385797.

Adding to 1221111523 its reverse (3251111221), we get a palindrome (4472222744).

The spelling of 1221111523 in words is "one billion, two hundred twenty-one million, one hundred eleven thousand, five hundred twenty-three".