2101212101 has 4 divisors (see below), whose sum is σ = 2101999692. Its totient is φ = 2100424512.

The previous prime is 2101212049. The next prime is 2101212103. The reversal of 2101212101 is 1012121012.

2101212101 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

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 438693025 + 1662519076 = 20945^2 + 40774^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2101212101 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101212103) 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, 389780 + ... + 395133.

It is an arithmetic number, because the mean of its divisors is an integer number (525499923).

Almost surely, 2^2101212101 is an apocalyptic number.

It is an amenable number.

2101212101 is a deficient number, since it is larger than the sum of its proper divisors (787591).

2101212101 is an equidigital number, since it uses as much as digits as its factorization.

2101212101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 787590.

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

The square root of 2101212101 is about 45838.9801479047. The cubic root of 2101212101 is about 1280.8254971693.

Adding to 2101212101 its reverse (1012121012), we get a palindrome (3113333113).

It can be divided in two parts, 2 and 101212101, that multiplied together give a palindrome (202424202).

The spelling of 2101212101 in words is "two billion, one hundred one million, two hundred twelve thousand, one hundred one".