221221012123 has 4 divisors (see below), whose sum is σ = 221244463440. Its totient is φ = 221197560808.

The previous prime is 221221012063. The next prime is 221221012169. The reversal of 221221012123 is 321210122122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221221012123 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221221012123.

It is not an unprimeable number, because it can be changed into a prime (221221012193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11711503 + ... + 11730376.

It is an arithmetic number, because the mean of its divisors is an integer number (55311115860).

Almost surely, 2^221221012123 is an apocalyptic number.

221221012123 is a deficient number, since it is larger than the sum of its proper divisors (23451317).

221221012123 is an equidigital number, since it uses as much as digits as its factorization.

221221012123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23451316.

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

Adding to 221221012123 its reverse (321210122122), we get a palindrome (542431134245).

The spelling of 221221012123 in words is "two hundred twenty-one billion, two hundred twenty-one million, twelve thousand, one hundred twenty-three".