21220111221523 has 2 divisors, whose sum is σ = 21220111221524. Its totient is φ = 21220111221522.

The previous prime is 21220111221479. The next prime is 21220111221559. The reversal of 21220111221523 is 32512211102212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21220111221523 - 2⁹ = 21220111221011 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220111221923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610055610761 + 10610055610762.

It is an arithmetic number, because the mean of its divisors is an integer number (10610055610762).

Almost surely, 2^{21220111221523} is an apocalyptic number.

21220111221523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220111221523 is an equidigital number, since it uses as much as digits as its factorization.

21220111221523 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 25.

Adding to 21220111221523 its reverse (32512211102212), we get a palindrome (53732322323735).

The spelling of 21220111221523 in words is "twenty-one trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty-one thousand, five hundred twenty-three".