21202120100101 has 4 divisors (see below), whose sum is σ = 21420698657932. Its totient is φ = 20983541542272.

The previous prime is 21202120100017. The next prime is 21202120100173. The reversal of 21202120100101 is 10100102120212.

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 10247675037601 + 10954445062500 = 3201199^2 + 3309750^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202120100101 - 2¹⁷ = 21202119969029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202120100701) 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, 109289278770 + ... + 109289278963.

It is an arithmetic number, because the mean of its divisors is an integer number (5355174664483).

Almost surely, 2^{21202120100101} is an apocalyptic number.

It is an amenable number.

21202120100101 is a deficient number, since it is larger than the sum of its proper divisors (218578557831).

21202120100101 is an equidigital number, since it uses as much as digits as its factorization.

21202120100101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218578557830.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21202120100101 its reverse (10100102120212), we get a palindrome (31302222220313).

The spelling of 21202120100101 in words is "twenty-one trillion, two hundred two billion, one hundred twenty million, one hundred thousand, one hundred one".