21001121101 has 4 divisors (see below), whose sum is σ = 21004717500. Its totient is φ = 20997524704.

The previous prime is 21001121087. The next prime is 21001121131. The reversal of 21001121101 is 10112110012.

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 7212255625 + 13788865476 = 84925^2 + 117426^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001121101 - 2⁹ = 21001120589 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 (21001121131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1789426 + ... + 1801123.

It is an arithmetic number, because the mean of its divisors is an integer number (5251179375).

Almost surely, 2^21001121101 is an apocalyptic number.

It is an amenable number.

21001121101 is a deficient number, since it is larger than the sum of its proper divisors (3596399).

21001121101 is an equidigital number, since it uses as much as digits as its factorization.

21001121101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3596398.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21001121101 its reverse (10112110012), we get a palindrome (31113231113).

The spelling of 21001121101 in words is "twenty-one billion, one million, one hundred twenty-one thousand, one hundred one".