221102121521 has 2 divisors, whose sum is σ = 221102121522. Its totient is φ = 221102121520.

The previous prime is 221102121509. The next prime is 221102121547. The reversal of 221102121521 is 125121201122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216359871025 + 4742250496 = 465145^2 + 68864^2 .

It is a cyclic number.

It is not a de Polignac number, because 221102121521 - 2¹⁴ = 221102105137 is a prime.

It is a super-2 number, since 2×221102121521² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221102121493 and 221102121502.

It is not a weakly prime, because it can be changed into another prime (221102121571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110551060760 + 110551060761.

It is an arithmetic number, because the mean of its divisors is an integer number (110551060761).

Almost surely, 2^221102121521 is an apocalyptic number.

It is an amenable number.

221102121521 is a deficient number, since it is larger than the sum of its proper divisors (1).

221102121521 is an equidigital number, since it uses as much as digits as its factorization.

221102121521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 20.

Adding to 221102121521 its reverse (125121201122), we get a palindrome (346223322643).

The spelling of 221102121521 in words is "two hundred twenty-one billion, one hundred two million, one hundred twenty-one thousand, five hundred twenty-one".