221221010105 has 4 divisors (see below), whose sum is σ = 265465212132. Its totient is φ = 176976808080.

The previous prime is 221221010089. The next prime is 221221010111. The reversal of 221221010105 is 501010122122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 501010122122 = 2 ⋅250505061061.

It can be written as a sum of positive squares in 2 ways, for example, as 147003994921 + 74217015184 = 383411^2 + 272428^2 .

It is not a de Polignac number, because 221221010105 - 2⁴ = 221221010089 is a prime.

It is a super-2 number, since 2×221221010105² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22122101006 + ... + 22122101015.

It is an arithmetic number, because the mean of its divisors is an integer number (66366303033).

Almost surely, 2^221221010105 is an apocalyptic number.

It is an amenable number.

221221010105 is a deficient number, since it is larger than the sum of its proper divisors (44244202027).

221221010105 is an equidigital number, since it uses as much as digits as its factorization.

221221010105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44244202026.

The product of its (nonzero) digits is 80, while the sum is 17.

Adding to 221221010105 its reverse (501010122122), we get a palindrome (722231132227).

The spelling of 221221010105 in words is "two hundred twenty-one billion, two hundred twenty-one million, ten thousand, one hundred five".