221021212123 has 2 divisors, whose sum is σ = 221021212124. Its totient is φ = 221021212122.

The previous prime is 221021212117. The next prime is 221021212171. The reversal of 221021212123 is 321212120122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221021212123 - 2¹⁷ = 221021081051 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221021212123.

It is not a weakly prime, because it can be changed into another prime (221021219123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110510606061 + 110510606062.

It is an arithmetic number, because the mean of its divisors is an integer number (110510606062).

Almost surely, 2^221021212123 is an apocalyptic number.

221021212123 is a deficient number, since it is larger than the sum of its proper divisors (1).

221021212123 is an equidigital number, since it uses as much as digits as its factorization.

221021212123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 221021212123 its reverse (321212120122), we get a palindrome (542233332245).

The spelling of 221021212123 in words is "two hundred twenty-one billion, twenty-one million, two hundred twelve thousand, one hundred twenty-three".