21021102101 has 4 divisors (see below), whose sum is σ = 21073524204. Its totient is φ = 20968680000.

The previous prime is 21021102079. The next prime is 21021102107. The reversal of 21021102101 is 10120112012.

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 19418701201 + 1602400900 = 139351^2 + 40030^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021102101 - 2¹⁴ = 21021085717 is a prime.

It is a super-2 number, since 2×21021102101² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021102107) 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, 26210450 + ... + 26211251.

It is an arithmetic number, because the mean of its divisors is an integer number (5268381051).

Almost surely, 2^21021102101 is an apocalyptic number.

It is an amenable number.

21021102101 is a deficient number, since it is larger than the sum of its proper divisors (52422103).

21021102101 is an equidigital number, since it uses as much as digits as its factorization.

21021102101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52422102.

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

Adding to 21021102101 its reverse (10120112012), we get a palindrome (31141214113).

The spelling of 21021102101 in words is "twenty-one billion, twenty-one million, one hundred two thousand, one hundred one".