221002020121 has 4 divisors (see below), whose sum is σ = 223029561700. Its totient is φ = 218974478544.

The previous prime is 221002020119. The next prime is 221002020137. The reversal of 221002020121 is 121020200122.

It is a happy number.

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 158572000521 + 62430019600 = 398211^2 + 249860^2 .

It is a cyclic number.

It is not a de Polignac number, because 221002020121 - 2¹ = 221002020119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221002020181) 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, 1013770626 + ... + 1013770843.

It is an arithmetic number, because the mean of its divisors is an integer number (55757390425).

Almost surely, 2^221002020121 is an apocalyptic number.

It is an amenable number.

221002020121 is a deficient number, since it is larger than the sum of its proper divisors (2027541579).

221002020121 is a wasteful number, since it uses less digits than its factorization.

221002020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2027541578.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 221002020121 its reverse (121020200122), we get a palindrome (342022220243).

The spelling of 221002020121 in words is "two hundred twenty-one billion, two million, twenty thousand, one hundred twenty-one".