21001212101 has 8 divisors (see below), whose sum is σ = 21296020440. Its totient is φ = 20706596352.

The previous prime is 21001212061. The next prime is 21001212143. The reversal of 21001212101 is 10121210012.

It can be written as a sum of positive squares in 4 ways, for example, as 4900140001 + 16101072100 = 70001^2 + 126890^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001212101 is a prime.

It is a super-2 number, since 2×21001212101² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001212161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178931 + ... + 272063.

It is an arithmetic number, because the mean of its divisors is an integer number (2662002555).

Almost surely, 2^21001212101 is an apocalyptic number.

It is an amenable number.

21001212101 is a deficient number, since it is larger than the sum of its proper divisors (294808339).

21001212101 is an equidigital number, since it uses as much as digits as its factorization.

21001212101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96295.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21001212101 its reverse (10121210012), we get a palindrome (31122422113).

The spelling of 21001212101 in words is "twenty-one billion, one million, two hundred twelve thousand, one hundred one".