212121202221001 has 4 divisors (see below), whose sum is σ = 212213069352900. Its totient is φ = 212029335089104.

The previous prime is 212121202220987. The next prime is 212121202221023. The reversal of 212121202221001 is 100122202121212.

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 202721925422025 + 9399276798976 = 14238045^2 + 3065824^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121202221001 - 2²¹ = 212121200123849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 212121202221001.

It is not an unprimeable number, because it can be changed into a prime (212121202291001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45933562486 + ... + 45933567103.

It is an arithmetic number, because the mean of its divisors is an integer number (53053267338225).

Almost surely, 2^{212121202221001} is an apocalyptic number.

It is an amenable number.

212121202221001 is a deficient number, since it is larger than the sum of its proper divisors (91867131899).

212121202221001 is an equidigital number, since it uses as much as digits as its factorization.

212121202221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91867131898.

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

Adding to 212121202221001 its reverse (100122202121212), we get a palindrome (312243404342213).

The spelling of 212121202221001 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred two million, two hundred twenty-one thousand, one".