221020233121 has 4 divisors (see below), whose sum is σ = 228641620500. Its totient is φ = 213398845744.

The previous prime is 221020233107. The next prime is 221020233127. The reversal of 221020233121 is 121332020122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121332020122 = 2 ⋅60666010061.

It can be written as a sum of positive squares in 2 ways, for example, as 67371912721 + 153648320400 = 259561^2 + 391980^2 .

It is a cyclic number.

It is not a de Polignac number, because 221020233121 - 2¹⁷ = 221020102049 is a prime.

It is a super-2 number, since 2×221020233121² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221020233127) 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, 3810693646 + ... + 3810693703.

It is an arithmetic number, because the mean of its divisors is an integer number (57160405125).

Almost surely, 2^221020233121 is an apocalyptic number.

It is an amenable number.

221020233121 is a deficient number, since it is larger than the sum of its proper divisors (7621387379).

221020233121 is an equidigital number, since it uses as much as digits as its factorization.

221020233121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7621387378.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 221020233121 its reverse (121332020122), we get a palindrome (342352253243).

The spelling of 221020233121 in words is "two hundred twenty-one billion, twenty million, two hundred thirty-three thousand, one hundred twenty-one".