201220122121 has 4 divisors (see below), whose sum is σ = 201726974212. Its totient is φ = 200713270032.

The previous prime is 201220122109. The next prime is 201220122127. The reversal of 201220122121 is 121221022102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121221022102 = 2 ⋅60610511051.

It can be written as a sum of positive squares in 2 ways, for example, as 168971145721 + 32248976400 = 411061^2 + 179580^2 .

It is a cyclic number.

It is not a de Polignac number, because 201220122121 - 2²⁵ = 201186567689 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201220122095 and 201220122104.

It is not an unprimeable number, because it can be changed into a prime (201220122127) 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, 253425450 + ... + 253426243.

It is an arithmetic number, because the mean of its divisors is an integer number (50431743553).

Almost surely, 2^201220122121 is an apocalyptic number.

It is an amenable number.

201220122121 is a deficient number, since it is larger than the sum of its proper divisors (506852091).

201220122121 is an equidigital number, since it uses as much as digits as its factorization.

201220122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506852090.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 201220122121 its reverse (121221022102), we get a palindrome (322441144223).

The spelling of 201220122121 in words is "two hundred one billion, two hundred twenty million, one hundred twenty-two thousand, one hundred twenty-one".