1021222211221 has 4 divisors (see below), whose sum is σ = 1022888153452. Its totient is φ = 1019556268992.

The previous prime is 1021222211197. The next prime is 1021222211231. The reversal of 1021222211221 is 1221122221201.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7654500100 + 1013567711121 = 87490^2 + 1006761^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021222211221 - 2¹⁵ = 1021222178453 is a prime.

It is a super-2 number, since 2×1021222211221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021222211231) 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, 832970196 + ... + 832971421.

It is an arithmetic number, because the mean of its divisors is an integer number (255722038363).

Almost surely, 2^{1021222211221} is an apocalyptic number.

It is an amenable number.

1021222211221 is a deficient number, since it is larger than the sum of its proper divisors (1665942231).

1021222211221 is an equidigital number, since it uses as much as digits as its factorization.

1021222211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1665942230.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1021222211221 its reverse (1221122221201), we get a palindrome (2242344432422).

The spelling of 1021222211221 in words is "one trillion, twenty-one billion, two hundred twenty-two million, two hundred eleven thousand, two hundred twenty-one".